Providing access to configurable private computer networks

ABSTRACT

Techniques are described for providing users with access to computer networks, such as to enable users to interact with a remote configurable network service in order to create and configure computer networks that are provided by the configurable network service for use by the users. Computer networks provided by the configurable network service may be configured to be private computer networks that are accessible only by the users who create them, and may each be created and configured by a client of the configurable network service to be an extension to an existing computer network of the client, such as a private computer network extension to an existing private computer network of the client. If so, secure private access between an existing computer network and new computer network extension that is being provided may be enabled using one or more VPN connections or other private access mechanisms.

This application is a continuation of U.S. patent application Ser. No.16/938,999, filed Jul. 26, 2020, which is a continuation of U.S. patentapplication Ser. No. 13/829,721, filed Mar. 14, 2013, now U.S. Pat. No.10,728,089, which is a continuation of U.S. patent application Ser. No.13/491,328, filed Jun. 7, 2012, now U.S. Pat. No. 8,578,003, which is acontinuation of U.S. patent application Ser. No. 12/332,214, filed Dec.10, 2008, now U.S. Pat. No. 8,230,050, which are hereby incorporated byreference herein in their entirety.

BACKGROUND

Many companies and other organizations operate computer networks thatinterconnect numerous computing systems to support their operations,such as with the computing systems being co-located (e.g., as part of alocal network) or instead located in multiple distinct geographicallocations (e.g., connected via one or more private or publicintermediate networks). For example, data centers housing significantnumbers of interconnected computing systems have become commonplace,such as private data centers that are operated by and on behalf of asingle organization, and public data centers that are operated byentities as businesses to provide computing resources to customers. Somepublic data center operators provide network access, power, and secureinstallation facilities for hardware owned by various customers, whileother public data center operators provide “full service” facilitiesthat also include hardware resources made available for use by theircustomers. However, as the scale and scope of typical data centers hasincreased, the task of provisioning, administering, and managing thephysical computing resources has become increasingly complicated.

The advent of virtualization technologies for commodity hardware hasprovided some benefits with respect to managing large-scale computingresources for many customers with diverse needs, allowing variouscomputing resources to be efficiently and securely shared by multiplecustomers. For example, virtualization technologies, such as thoseprovided by VMWare, XEN, or User-Mode Linux, may allow a single physicalcomputing machine to be shared among multiple users by providing eachuser with one or more virtual machines hosted by the single physicalcomputing machine, with each such virtual machine being a softwaresimulation acting as a distinct logical computing system that providesusers with the illusion that they are the sole operators andadministrators of a given hardware computing resource, while alsoproviding application isolation and security among the various virtualmachines. Furthermore, some virtualization technologies are capable ofproviding virtual resources that span one or more physical resources,such as a single virtual machine with multiple virtual processors thatspans multiple distinct physical computing systems.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are network diagrams illustrating example embodiments ofinteractions that involve remote clients creating and configuringprivate computer networks.

FIG. 2 is a network diagram illustrating an example embodiment ofinterconnected computing systems for use in providing computer networksto clients.

FIG. 3 is a block diagram illustrating example computing systemssuitable for executing an embodiment of a system for providing computernetworks for use by remote clients.

FIGS. 4A and 4B illustrate a flow diagram of an example embodiment of aConfigurable Network Service Manager routine.

FIG. 5 illustrates a flow diagram of an example embodiment of a NodeCommunication Manager routine.

FIG. 6 illustrates a flow diagram of an example embodiment of anExternal Communication Manager routine.

FIG. 7 illustrates a flow diagram of an example embodiment of a RemoteResource Service Access routine.

FIG. 8 illustrates a flow diagram of an example embodiment of a VPNCreation Fulfillment routine.

DETAILED DESCRIPTION

Techniques are described for providing users with access to computernetworks, such as under the control of a configurable network serviceavailable to remote users. In at least some embodiments, a remote usermay interact with a configurable network service over public networks inorder to create and configure a computer network for use by the user,with the configured computer network being provided by the configurablenetwork service and including multiple computing nodes that aremaintained by or otherwise under the control of the configurable networkservice. After configuring such a computer network, the user mayinteract from one or more remote locations with the computer networkbeing provided to the user by the configurable network service, such asto execute programs on the computing nodes of the provided computernetwork. The configurable network service may in at least someembodiments be a fee-based service, such that users of the configurablenetwork service are customers that pay fees to the configurable networkservice for at least some of the functionality provided by theconfigurable network service. In addition, in at least some embodiments,some or all of the described techniques are automatically performed byembodiments of a Configurable Network Service Manager module, optionallyin conjunction with other communication manager modules, as described ingreater detail below.

In at least some embodiments, at least some of the computer networksprovided by the configurable network service are private computernetworks that are accessible only by the users of the configurablenetwork service on whose behalf the provided computer networks arecreated and configured (or by others for whom access is explicitlyconfigured). For example, the configurable network service may provide auser who is a client of the configurable network service with secureprivate access to a computer network provided for the client, such as byenabling a VPN (“virtual private network”) connection or other secureconnection between one or more remote computing systems of the clientand the provided computer network, or may use other security and/orauthentication techniques to enable the client to remotely interact withthe provided computer network in a private and secure manner. Inaddition, in at least some embodiments, at least some of the computernetworks provided by the configurable network service are each createdand configured by a client to be an extension to an existing computernetwork of the client, such as a private computer network extension toan existing remote private computer network of the client (e.g., aremote corporate network of a client that is a corporate entity). Insuch embodiments, secure private access between the existing computernetwork and the new computer network extension that is being providedmay similarly be enabled using one or more VPN connections or otherprivate connections. Additional details related to establishing accessof a client to a computer network provided by an embodiment of theconfigurable network service are included below.

Clients of the configurable network service may create and configurecomputer networks provided by the configurable network service invarious manners in various embodiments. In at least some embodiments,the configurable network service provides one or more APIs (“applicationprogramming interfaces”) that enable computing systems of clients toprogrammatically interact with the configurable network service toperform some or all actions in creating, configuring, and initiating useof computer networks provided by the configurable network service, whilein at least some embodiments users who are clients of the configurablenetwork service may interactively interact with the configurable networkservice to perform some or all such actions (e.g., via a GUI, orgraphical user interface, or other console provided by the configurablenetwork service), whether instead of or in addition to performing suchactions via use of such APIs. In some embodiments, a GUI available tousers may be based on an underlying API that is alternatively availableto users, while in other embodiments a GUI may be implemented in othermanners. In addition, interactions between computing devices of clientsand the configurable network service may be based at least in part onelectronic messages (e.g., email messages) sent between the clientcomputing devices and the configurable network service, such as inaccordance with a message-based API of the configurable network service.

For example, in at least some embodiments, a client may interact with anembodiment of the configurable network service to specify configurationinformation for a computer network to be provided for the client, withthe configuration information optionally including a variety of types ofinformation such as one or more of the following non-exclusive list:multiple specified network addresses to be assigned to multiplecomputing nodes of the provided computer network; specified networktopology information for the provided computer network; and specifiednetwork access constraints for the provided computer network. Themultiple specified network addresses may include, for example, one ormore ranges of network addresses, and if the computer network beingprovided is an extension to a remote private computer network of aclient, may correspond to a subset of virtual and/or private networkaddresses used for the remote private computer network. The specifiednetwork topology information may indicate, for example, subsets of thecomputing nodes of the provided computer network to be grouped togetheror that are to otherwise share common intercommunicationcharacteristics, such as by specifying one or more networking devices tobe part of the provided computer network (e.g., routers, switches, etc.)and that manage or are otherwise associated with computing nodes havingparticular specified network addresses, or by otherwise indicatingsubnets of the provided computer network or other groupings of thecomputing nodes of the provided computer network. The specified networkaccess constraint information may indicate, for example, for each of oneor more of the provided computer network's computing nodes, which othercomputing nodes may intercommunicate with the computing node and/or thetypes of communications allowed to and/or from the computing node,including whether the computing nodes of the provided computer networkare allowed to communicate with any computing nodes external to theprovided computer network (or in cases in which the provided computernetwork is an extension to an existing other computer network, whetherthe computing nodes of the provided computer network are allowed tocommunicate with any computing nodes external to that other computernetwork to which it belongs). Additional details related to creating andconfiguring computer networks provided by embodiments of theconfigurable network service are included below.

In addition, in at least some embodiments, the computing nodes used bythe configurable network service to provide computer networks to clientsmay have various forms, such as physical computing systems and/orvirtual machines that are each hosted on one or more physical computingsystems. For example, in some embodiments, the configurable networkservice may include a large number of computing nodes that are providedby the configurable network service to be available for use in computernetworks provided to clients, such as in one or more data centers in oneor more geographical locations. In addition, in at least someembodiments, some or all of the computing nodes provided by theconfigurable network service are interconnected by one or moreintermediate physical networks, and the computer networks provided toclients may be virtual (or “logical”) networks that are overlaid overthe intermediate physical networks by using the intermediate physicalnetworks as a substrate network. Furthermore, in at least someembodiments, at least some of the computing nodes may be used by aprogram execution service (or “PES”) that executes multiple programs onbehalf of multiple customers or other users of the program executionservice. Additional details related to computing nodes and underlyingcomputer networks are included below, and additional details related toexample embodiments of providing virtual networks to clients andproviding a program execution service are included in U.S. applicationSer. No. 11/394,595 (Attorney Docket Number 120137.524), filed Mar. 31,2006 and entitled “Managing Communications Between Computing Nodes;” inU.S. application Ser. No. 11/395,463 (Attorney Docket Number120137.525), filed Mar. 31, 2006 and entitled “Managing Execution ofPrograms by Multiple Computing Systems;” in U.S. application Ser. No.11/692,038 (Attorney Docket Number 120137.554), filed Mar. 27, 2007 andentitled “Configuring Intercommunications Between Computing Nodes;” inU.S. application Ser. No. 12/060,074 (Attorney Docket Number120137.576), filed Mar. 31, 2008 and entitled “ConfiguringCommunications Between Computing Nodes;” and in U.S. application Ser.No. 11/764,739 (Attorney Docket Number 120137.555), filed Jun. 18, 2007and entitled “Providing Enhanced Access To Remote Services;” each ofwhich is incorporated herein by reference in its entirety.

In some embodiments, a client may further configure a computer networkprovided by the configurable network service to provide access to one ormore other network-accessible services that are remote from the providedcomputer network, such as other remote network-accessible services thatare accessible over the Internet or other public networks, or that areotherwise external to and not part of the provided computer network. Atleast some such remote services may in some embodiments be affiliatedwith the configurable network service (e.g., provided by an operator ofthe configurable network service or an affiliated entity; provided byanother client of the configurable network service, such as via acomputer network being provided to that other client by the configurablenetwork service, etc.), and at least some such remote services in someembodiments may instead be independent of the configurable networkservice. Such other remote services may have various forms in variousembodiments, including services that provide network access to one ormore types of computing-related resources (e.g., storage services thatprovide access to stored data resources, messaging services that provideaccess to message queue resources or other stored message resources,database services that provide access to stored database resources,program execution services that provide access to program executionresources, etc.) for use by remote computing systems, or that otherwiseprovide access to information or functionality or other resources of use(e.g., a service that provides stock quote information resources orsearch query results resources; a service that provides photo sharingfunctionality resources or social networking capability resources;etc.). In some situations, an embodiment of the configurable networkservice may provide a plurality of computing nodes at a data center orother geographical location, and may use subsets of those computingnodes to provide different computer networks to different clients (e.g.,with each provided computer network being a distinct virtual networkthat shares a common substrate network)—in such situations, one clientmay configure the provided computer network for that client to provideaccess to one or more network-accessible remote services that areprovided by other of the clients using other of the provided computernetworks at that geographical location, such as without the one clientbeing aware that those remote resources are physically provided by othercomputing nodes at the same geographical location.

In at least some embodiments, a client may configure a provided computernetwork for the client to include a mechanism for accessing a particularresource service, with the access mechanism able to be configured toprovide various functionality for that provided computer network. As oneparticular example, in some embodiments, a provided virtual computernetwork that has multiple associated virtual network addresses mayassign one (or more) of those virtual network addresses to represent aparticular remote resource service, so that computing nodes or otherparticipants of the provided computer network may communicate with theremote resource service external to the provided computer network viathe representative assigned network address that is local to theprovided computer network. In this manner, even a provided computernetwork that is configured with network access constraints to preventcommunications external to the provided computer network (e.g., toprevent communications that would pass through the Internet or one ormore other public networks) may be configured to allow communications toa particular external remote resource service via such a configuredaccess mechanism that is part of the provided computer network.

Furthermore, various techniques may be used in at least some embodimentsto provide enhanced security for such communications from providedcomputer networks to remote resource services via configured accessmechanisms of the provided computer networks. For example, in at leastsome embodiments, a particular remote resource service may have apublicly accessible interface that is available to users via theInternet or other public networks (e.g., via one or more public networkaddresses and associated domain names), but may also implement aninterface that is directly accessible from the substrate network that isused by the configurable network service to interconnect computingnodes, such as if the particular remote resource service is provided bythe same operator as the configurable network service or is otherwiseaffiliated with the configurable network service. If such a directlyaccessible interface is implemented on the substrate network for aparticular remote resource service, one or more provided computernetworks of the configurable network service may each have a configuredaccess mechanism for that remote resource service that directscommunications intended for that remote resource service to thatinterface implemented on the substrate network, rather than to a remotepublicly accessible interface of the remote resource service. Thatremote resource service may accordingly opt to, in at least some suchembodiments and situations, provide some or all of the functionality ofthe remote resource service for at least some client requests in amanner local to the configurable network service (e.g., if one or morecomputing nodes of the configurable network service are used toimplement that local functionality), while in other embodiments andsituations the remote resource service may provide some or allfunctionality for at least some such client requests by managingcommunications between the substrate network of the configurable networkservice over one or more public networks to the remote location of theremote resource service in a secure manner. Alternatively, in at leastsome embodiments, the configurable network service may performadditional actions for at least some remote resource services to providesecure communications from the configurable network service over one ormore public networks to the remote location of the remote resourceservice in a similar manner, such as by encrypting the communications ina manner that is accessible to the remote resource service and/or byauthenticating the communications as being from a trusted source.Additional details related to accessing remote resources from providedcomputer networks are included below.

Furthermore, in at least some such embodiments, a provided computernetwork for a client may be configured to receive access to a particularsubset of the computing-related resources provided by anetwork-accessible remote resource service, such as a subset thatcorresponds to that client. As one example, a remote resource servicemay use distinct namespaces that partition its provided resources intodifferent groups that have different access rights and that areseparately referenced, such that different resources in differentnamespaces may have the same local name or other identifier but bereferenced separately based on those namespaces, and with a particularnamespace corresponding to a particular client. If so, a providedcomputer network for a client may include one or more mechanisms foraccessing a particular remote resource service that are each configuredto automatically correspond to a particular namespace of that remoteresource service, such that computing nodes of the provided computernetwork may use a configured access mechanism to obtain access toresources within the particular corresponding namespace of that client.Furthermore, in at least some embodiments, the computing nodes of theprovided computer network may be unaware of the namespace to which aconfigured mechanism corresponds, such that a computing node may send arequest or other message to the remote resource service that indicatesthe name or other identifier of a resource of interest within thecontext of the namespace, but without an actual indication of thenamespace. If so, the configured access mechanism may automaticallymodify or translate the message so that the indicated name or otheridentifier is associated with the namespace corresponding to theconfigured access mechanism, with the modifying or translatingoptionally being transparent to the computing node that sent themessage.

The configuring of the provided computer network and the accessmechanism representing a remote resource service may be performed invarious manners. For example, in some situations a client may specify anexisting namespace of the client within the remote resource service,such as a namespace in which the client has previously stored orotherwise used particular resources.

Alternatively, in other embodiments, the configurable network servicemay automatically initiate the use of a new namespace within the remoteresource service for new resources that are accessed from the providedcomputer network, such as by interacting with the remote resourceservice to create the new namespace. Such interactions with the remoteresource service may be performed at various times, such as when theclient is creating and configuring the provided computer network, orinstead later (e.g., when a computing node on the provided computernetwork first tries to access the remote resource service via aconfigured access mechanism). Furthermore, in at least some embodimentsand situations, the configurable network service may generate a uniqueidentifier that is associated with the provided computer network and usethat identifier to reference the new namespace, while in otherembodiments the remote resource service may provide such an identifieror other indication of a new namespace that is created. In either case,the client and computing nodes of the provided computer network mayoptionally be unaware of the new automatically initiated namespaceand/or the unique identifier used by the configurable network service toreference the new namespace. Alternatively, in some embodiments, theclient may specify the identifier to be used by the configurable networkservice to be associated with a computer network provided to the clientby the configurable network service, whether or not the client is awarethat the identifier will be used by the configurable network service toreference a new namespace or instead in other manners. Furthermore, inat least some embodiments, the identifier associated with a computernetwork provided to a client may be an identifier associated with theclient, such as if the client has a single provided computer network,while in other embodiments the provided computer network identifiers aredistinct from any client-specific identifiers. Additional detailsrelated to using namespaces are included below.

In addition, in at least some such embodiments, the access mechanismthat a provided computer network for a client uses to access resourcesfrom a particular remote resource service may be configured to assistthe remote resource service in authenticating or validatingcommunications that are received from the provided computer network,such as to validate that the communications are sent from a particularlocation (e.g., so as to prevent even that same client from accessingparticular resources from another location). For example, at least someremote resource services may allow or require that resources provided bythe remote resource services each have one or more associated accesscontrol indicators (e.g., names or other textual identifiers, numericidentifiers, tags or other access keys, credentials, etc.), such thatsuch a resource may be accessed by an external requester only if therequester supplies all of those associated indicators. For such remoteresource services, one of the access control indicators used by thecomputing nodes of a provided computer network for a client may be anidentifier corresponding to that client, such as a customer identifierfor that client with that remote resource service. If only that singlecustomer identifier for a client is associated with a resource, thenthat client may be able to access that resource from other remotecomputing systems of the client by supplying the same single customeridentifier. Such a resource may, for example, be created in response toa request from the client or otherwise accessed and associated (e.g.,temporarily) with that client.

However, in at least some embodiments, a configured access mechanismthat a provided computer network for a client uses to access resourcesfrom a particular remote resource service may be configured to modifycommunications being sent to the remote resource service to include oneor more other additional access control indicators. Such otheradditional access control indicators may include, for example, anidentifier corresponding to the provided computer network that isautomatically generated by the configurable network service, and in atleast some embodiments the client and/or the computing nodes of theprovided computer network may be unaware of the particular additionalaccess control indicators that are used or even unaware of the existenceand use of any such additional access control indicators. If the one ormore additional access control indicators are not known to the client,then the client may not access those resources other than from theprovided computer network via that configured access mechanism, sincethe client will not otherwise supply all the indicators associated withsuch a resource in a request for access to that resource. Thus, aspreviously noted, such additional access control indicators may be usedby a remote resource service as an indicator of the source or locationof a request for access to a resource, such that requests from otherlocations are not given access to the resource. Alternatively, requestsfrom other locations may be given different access to such a resource,such as to configure a resource to allow write or other modificationaccess to the resource only if all of the access control indicators forthe resource are supplied, but to allow read or other access to theresource in other circumstances, such as by the client from anotherlocation if the client-specific identifier is supplied, by anyonewithout supplying any of the access control indicators, etc. Inaddition, such additional access control indicators may have variousforms, such as an automatically generated random alphanumeric indicator,an indication of an actual geographical location associated with aprovided computer network, etc.

In a manner similar to that with the use of namespaces, the configuringof the access mechanism for a provided computer network to use one ormore such additional access control indicators may be performed invarious manners. For example, in some embodiments a client may specifyone or more additional indicators to be associated with a providedcomputer network for use by a configured access mechanism to a remoteresource service. Alternatively, in other embodiments, the configurablenetwork service may automatically initiate the use of one or more newadditional indicators for a configured access mechanism to a remoteresource service for a provided computer network (e.g., by generatingand using a unique identifier that is associated with the providedcomputer network), such that new resources that are accessed from thatremote resource service via that configured access mechanism areaccessible only from that provided computer network. In addition, asdiscussed in greater detail below, some embodiments of the configurablenetwork service may use various modules to manage communications betweencomputing nodes of a provided computer network, such as to facilitatetransmission of the communications over a substrate network, and if soone or more such modules may be configured to implement a particularaccess mechanism by automatically modifying communications to includenamespace identifiers and/or access control indicators and/or byforwarding communications (optionally after modification) to aparticular remote resource service over one or more public networks.Additional details related to implementing access mechanisms, includingto assist remote resource services in validating location-specificcommunications from provided computer networks, are included below.

In at least some embodiments, the configurable network service furtherprovides an API that enables clients to programmatically interact withthe configurable network service to cause the configurable networkservice to take actions that facilitate establishing remote access ofthe clients to the computer networks provided to them by theconfigurable network service. Such a remote access establishment API mayperform various actions in various embodiments, and in at least someembodiments assists a client in establishing a VPN connection from aremote location of the client to the computer network being provided forthe client by the configurable network service. As previously noted, insome situations a client may have a remote private computer networkexternal to the configurable network service, and the computer networkthat is created and provided by the configurable network service may bean extension to that remote private network or otherwise connected tothat remote private network. In other situations, a client may use oneor more other remote computing systems to access and interact with thecomputer network provided by the configurable network service. In eithersituation, the client may in at least some embodiments use a VPNconnection or other secure connection from the remote private network orother remote computing system(s) to the computer network provided by theconfigurable network service. In such embodiments, the remote accessestablishment API provided by the configurable network service may, whenprogrammatically invoked by a client of the configurable networkservice, cause the configurable network service to initiate provision tothe client of one or more appropriate networking components to allow theremote private network or other remote computing system(s) of the clientto establish a VPN connection or other secure connection to the computernetwork provided by the configurable network service. Such networkingcomponents may include, for example, one or more hardware devices (e.g.,a router or other networking device), software components, and/or groupsof configuration information.

For example, in some embodiments, invocation of the remote accessestablishment API by a client causes the configurable network service tointeract with a merchant to purchase or otherwise acquire an appropriaterouter device or other hardware networking device(s) that are deliveredto a remote location of the client, and causes appropriately configuredsoftware or other configuration information for the acquired networkingdevice(s) to be delivered to the client, such that the device(s) whenconfigured with the software or based on the configuration informationand connected to one or more remote computing systems of the client willinitiate contact with the computer network provided for the client bythe configurable network service. In this manner, after the networkingdevice(s), software and/or configuration information are received by theclient, the client may, for example, attach the received networkingdevice(s) to the remote private network or other remote computingsystem(s), and use the software and/or configuration information toconfigure the received networking device(s). The configured networkingdevice(s) may then automatically contact the computer network providedfor the client and establish the VPN connection to enable private secureaccess of the client to the provided computer network. In othersituations, the configured networking device(s) may first automaticallycontact a configured computing system of the configurable networkservice in order to obtain additional configuration information specificto the computer network provided for the client, and then subsequentlyautomatically establish the VPN connection to that provided computernetwork.

In such embodiments, the merchant used to supply the networkingdevice(s) to a client may have various forms, such as an online merchantor other retailer that is operated by the same operator who operates theconfigurable network service or that is otherwise affiliated with theconfigurable network service, or instead a third-party merchant that isunaffiliated with the configurable network service. The hardwaredevice(s) to be used may similarly be selected in various manners invarious embodiments, including based on compatibility with the computernetwork provided by the configurable network service and/or with theremote computing system(s) in use by the client, such as may beautomatically detected and/or specified by the client. Furthermore, insome embodiments, multiple alternatives may be available from which theclient may select, such as may be specified by the client when initiallyinvoking the remote access establishment API, or in response to a laterquery from the configurable network service (e.g., a query thatspecifies the multiple alternatives from which the client may select).In other embodiments, a single type of networking device or otherhardware device may be used. In addition, the configured software and/orother configuration information may be supplied to the client fromvarious sources (e.g., by the same merchant that supplies the networkingdevice(s), directly by the configurable network service, or by anotherentity), and may be supplied in various manners (e.g., by electronicallytransmitting the software and/or configuration information to theclient; by storing the software and/or configuration information on aphysical device-readable medium, such as a DVD or USB memory key, andphysically delivering that medium to the client; by storing the softwareand/or configuration information on the networking device(s) before theyare delivered to the client, such as to pre-configure the device(s);etc.). In addition, in some embodiments, configured software that isprovided to the client may be sufficient to establish the VPNconnection, such as when used with one or more computing systems orother hardware devices that the client already has at the remotelocation.

Furthermore, the acquisition of a hardware device from a retailer orother third-party entity for a client may be performed in variousmanners in various embodiments, such as to purchase the device orinstead acquire it in another manner (e.g., obtain it for lease, rent,temporary evaluation, etc.), and may in some embodiments include theconfigurable network service providing payment to the retailer and thenseparately obtaining payment from the client (e.g., with the paymentfrom the client being more than, less than or the same as the payment tothe retailer), or instead having the client provide payment directly tothe retailer (e.g., by the configurable network service providing theretailer with payment information for the client, by the configurablenetwork service providing the retailer with information for use incontacting or otherwise interacting with the client to obtain thepayment information, by having the retailer use previously obtainedinformation from the client to obtain the payment, etc.). In addition,while in some embodiments the initiated acquisition of a hardware devicefrom a retailer for a client causes the delivery of the hardware devicefrom the retailer directly to a remote location of the client, in otherembodiments the configurable network service may perform the acquisitionin other manners, such as to initially take delivery of the hardwaredevice and then deliver it to the client (e.g., after configuring thehardware device with appropriate software and/or configurationinformation, or instead by forwarding the hardware device to the clientin the same form that it was received). Additional details regardingactions in various embodiments by the configurable network service tofulfill a client's programmatic invocation of the remote accessestablishment API are described below.

For illustrative purposes, some embodiments are described below in whichspecific types of computing nodes, networks, communications, andconfiguration operations are performed. These examples are provided forillustrative purposes and are simplified for the sake of brevity, andthe inventive techniques may be used in a wide variety of othersituations, some of which are discussed below. For example, in someembodiments, the computer networks that are created and configured foraccess by clients are private computer network extensions to existingprivate computer networks of those clients, while in other embodimentsthe created and configured computer networks may be standalone computernetworks that are not extensions to other computer networks and/or maybe public computer networks that are not privately accessible by theclient on whose behalf they are created and configured. In addition, insome embodiments the computer networks provided by the configurablenetwork service use computing nodes that are provided by and controlledby the configurable network service, while in other embodiments at leastsome such computing nodes that are used for provided computer networksmay be controlled or maintained by others (e.g., by third-parties, bythe clients, etc.) but made available for use with the configurablenetwork service.

FIG. 1A is a network diagram illustrating an example embodiment of aconfigurable network service that enables remote clients to create andconfigure computer networks for use by the clients. In this example, thecomputer networks that are created and configured are private networkextensions to existing private computer networks of clients, and aConfigurable Network Service 105 provides such functionality to clients(not shown) over one or more public networks 100 (e.g., over theInternet). Thus, the remote clients may use the Configurable NetworkService (“CNS”) 105 to dynamically modify the size and/or capabilitiesof their private computer networks, such as by using cloud computingtechniques over the public networks 100.

In particular, in the example of FIG. 1A, a number of clients (notshown) are interacting over a public network 100 with a Manager module110 to create and configure various private computer network extensions120 to remote existing client private networks 130, with at least someof the computer network extensions 120 being configured to enable secureprivate access from one or more corresponding client private networks130 over the public network 100 (e.g., via VPN connections establishedover interconnections 100 a and 100 b). In this example embodiment, theManager module 110 assists in providing functionality of the CNS 105 tothe remote clients, such as in conjunction with various other modules(not shown) of the CNS 105 and various computing nodes and networkingdevices (not shown) that are used by the CNS 105 to provide the privatecomputer network extensions 120. In at least some embodiments, the CNSManager module 110 may execute on one or more computing systems (notshown) of the CNS 105, and may provide one or more APIs that enableremote computing systems to programmatically interact with the module110 to access some or all functionality of the CNS 105 on behalf ofclients (e.g., to create, configure, and/or initiate use of privatenetwork extensions 120). In addition, in at least some embodiments,clients may instead manually interact with the module 110 (e.g., via auser interface provided by the module 110) to perform some or all suchactions.

The public network 100 may be, for example, a publicly accessiblenetwork of linked networks, possibly operated by distinct parties, suchas the Internet. The remote client private networks 130 may each includeone or more existing private networks, such as a corporate or otherprivate network (e.g., home, university, etc.) that is partially orwholly inaccessible to non-privileged users, and that includes computingsystems and/or other networked devices of a client. In the illustratedexample, the provided network extensions 120 each include multiplecomputing nodes (not shown), at least some of which are provided by orotherwise under the control of the CNS 105, and each of the providednetwork extensions 120 may be configured in various ways by the clientsfor whom they are provided. Each of the network extensions 120 in theillustrated embodiment may be a private computer network that isaccessible only by the client that creates it, although in otherembodiments at least some computer networks provided by the CNS 105 forclients may be publicly accessible and/or may be standalone computernetworks that are not extensions to other existing computer networks.Similarly, while the provided computer networks 120 in the example areextensions to remote client computer networks 130 that are privatenetworks, in other embodiments the provided computer networks 120 may beextensions to client computer networks 130 that are not privatenetworks.

Private access between a remote client private computer network 130 andcorresponding private computer network extension 120 provided for aclient may be enabled in various ways, such as by establishing a VPNconnection or other secure connection between them that allowsintercommunication over the public network 100 in a secure privatemanner. For example, the CNS 105 may automatically perform appropriateconfiguration on its computing nodes and other computing systems toenable VPN access to a particular private network extension 120 of aclient, such as by automatically configuring one or more VPN mechanismshosted by the CNS 105 (e.g., software and/or hardware VPN mechanisms),and/or may automatically provide appropriate configuration informationto the client (e.g., credentials, access points, and/or otherparameters) to allow a VPN mechanism hosted on the remote client privatenetwork 130 to establish the VPN access. After VPN access has beenappropriately enabled and/or configured, a VPN connection may beestablished between the remote client private network and the privatenetwork extension, such as initiated by the client using IPsec(“Internet Protocol Security”) or other appropriate communicationtechnologies. For example, in some embodiments, a VPN connection orother secure connection may be established to or between networks thatuse MPLS (“Multi Protocol Label Switching”) for data transmission, suchas instead of an IPsec-based VPN connection. Additional detailsregarding enabling and establishing secure connections, such as inresponse to client invocation of a corresponding remote accessestablishment API provided by the CNS 105, are discussed in greaterdetail elsewhere.

In addition, in the illustrated embodiment, various network-accessibleremote resource services 140 are available to remote computing systemsover the public network 100, including to computing systems on theremote client private networks 130. The resource services 140 mayprovide various functionality to the remote computing systems, such asfor at least some of the resource services 140 to provide remotecomputing systems with access to various types of computing-relatedresources. Furthermore, at least some of the private network extensions120 that are provided by the CNS 105 may be configured to provideprivate or other specialized access to at least some of the remoteresource services 140, with that provided access optionally appearing tocomputing nodes of the private network extensions 120 as being locallyprovided via virtual connections 115 that are part of the privatenetwork extensions 120, although the actual communications with theremote resource services 140 may occur over the public networks 100(e.g., via interconnections 100 b and 100 c). Additional detailsregarding establishing and using such private or other specializedaccess to remote resource services are discussed in greater detailelsewhere.

As previously noted, the provided network extensions 120 may each beconfigured by clients in various manners. For example, in at least someembodiments, the CNS 105 provides multiple computing nodes that areavailable for use with network extensions provided to clients, such thateach provided network extension 120 may include a client-configuredquantity of multiple such computing nodes that are dedicated for use aspart of the provided network extension. In particular, a client mayinteract with the module 110 to configure a quantity of computing nodesto initially be included in a computer network provided for the client(e.g., via one or more programmatic interactions with an API provided bythe CNS 105). In addition, in at least some such embodiments, computingnodes may later be dynamically added to or removed from a providedcomputer network of a client (e.g., via one or more programmaticinteractions with an API provided by the CNS 105), such as after theprovided computer network has already been in use by the client (e.g.,by indicating to initiate or terminate execution of particular programson particular computing nodes). Furthermore, the CNS 105 may providemultiple different types of computing nodes in at least someembodiments, such as, for example, computing nodes with variousperformance characteristics (e.g., processor speed, memory available,storage available, etc.) and/or other capabilities. If so, in at leastsome such embodiments, a client may specify the types of computing nodesto be included in a provided computer network for the client.

In addition, in at least some embodiments, a client may interact withthe module 110 to configure network addresses for a computer networkprovided for the client (e.g., via one or more programmatic interactionswith an API provided by the CNS 105), and network addresses may later bedynamically added, removed or modified for a provided computer networkof a client in at least some such embodiments, such as after theprovided computer network has already been in use by the client. Forexample, if a particular provided computer network that is beingconfigured is an extension to an existing remote client computernetwork, the client may specify one or more address ranges (e.g., aClassless Inter-Domain Routing (“CIDR”) address block) or other groupsof network addresses that are a subset of the network addresses used bythe existing remote client computer network, such that the specifiednetwork addresses are used for the computing nodes of the providedcomputer network. Such configured network addresses may in somesituations be virtual or private network addresses that are not directlyaddressable from computing systems on the public network 100 (e.g., ifthe existing remote client computer network and the correspondingprovided network extension use network address translation techniquesand/or virtual networking techniques for the client computer network andits provided network extension), while in other situations at least someof the configured network addresses may be public network addresses thatare directly addressable from computing systems on the public network100 (e.g., a public network address that is a static Internet-routableIP address or other non-changing network address). In other embodiments,the CNS 105 may automatically select network addresses to be used for atleast some computing nodes of at least some provided computer networkextensions, such as based on network addresses that are available foruse by the CNS 105, based on selecting network addresses that arerelated network addresses used by remote existing computer networkscorresponding to the provided computer networks, etc. In addition, in atleast some embodiments in which the CNS 105 provides virtual networks toclients, such as by using overlay networks on a substrate network, eachclient may be allowed to specify any network addresses to be used fortheir provided computer networks, even if multiple clients specify thesame or overlapping network addresses for their respective providedcomputer networks—in such embodiments, the CNS 105 manages the networkaddresses distinctly for each client, such that a first client may havea first computing node associated with a particular specified networkaddress for the first client's provided computer network, while adistinct second client may have a distinct second computing nodeassociated with the same particular specified network address for thesecond client's provided computer network. Once network addresses areconfigured or otherwise determined for a provided computer network, theCNS 105 may assign the network addresses to various of the computingnodes selected for the provided computer network, such as in a randommanner, by using DHCP (“Dynamic Host Configuration Protocol”) or othertechniques for dynamic assignment of network addresses, etc. Inaddition, even if public network addresses are used for a particularcomputer network, the CNS 105 may map one or more of those publicnetwork addresses for use in other manners, such as to use a particularpublic network address to act as an access mechanism for a particularremote resource service as described in greater detail elsewhere, sothat communications sent to that particular public network address bycomputing nodes of that particular computer network will be forwarded tothe corresponding remote resource service rather than to anothercomputing system on the Internet or other network to which thatparticular public network address is assigned. FIG. 1B providesadditional details regarding an example of using configured networkaddresses to route communications within a provided computer network.

In addition, in at least some embodiments, a client may interact withthe module 110 to configure network topology information for a computernetwork provided for the client (e.g., via one or more programmaticinteractions with an API provided by the CNS 105), and such networktopology information may later be dynamically modified for a providedcomputer network in at least some such embodiments, such as after theprovided computer network has already been in use by the client. Forexample, a client may specify particular types of networking devices(e.g., routers, switches, etc.) and/or other network devices or nodes(e.g., firewalls, proxies, network storage devices, printers, etc.) tobe part of the provided computer network, and/or may specify subsets ofthe computing nodes of the provided computer network to be groupedtogether or that are to otherwise share common intercommunicationcharacteristics (e.g., a particular subset of computing nodes that arepart of a subnet for which intercommunications are not filtered and/orthat are associated with a particular networking device). In addition,the specified configuration information for a provided computer networkmay in at least some embodiments include routing information or otherinterconnectivity information between networking devices and/or groupsof computing devices. Furthermore, in at least some embodiments, the CNS105 may provide available computing nodes in multiple geographicallocations (e.g., in multiple geographically distributed data centers),and the configuration information specified by a client for a providedcomputer network may further indicate one or more geographical locationsin which computing nodes of the provided computer network are to belocated (e.g., to provide fault tolerance among the computing nodes of aprovided computer network by having them located in multiplegeographical locations), and/or may otherwise provide information aboutpreferences or requirements of how the computing nodes of the providedcomputer network are to interoperate that is used by the CNS 105 toselect one or more such geographical locations (e.g., minimum or maximumnetwork latency or bandwidth for computing node intercommunications;minimum or maximum network proximity between computing nodes; minimum ormaximum geographic proximity between computing nodes; having localaccess to particular resources or functionality that is not available inall such geographic locations; having specified locations relative toother external computing systems, such as to a remote computer networkof the client and/or to a remote resource service; etc.).

As discussed in greater detail elsewhere, in at least some embodiments,the interconnections and intercommunications between computing nodes ofa provided computer network are managed using an underlying substratenetwork of the CNS 105, and if so, some or all of the configured networktopology information may be simulated in at least some such embodimentsusing the underlying substrate network and corresponding modules of theCNS 105. For example, each of the computing nodes provided by the CNS105 may be associated with a node communication manager module of theCNS 105 that manages communications to and from its associated computingnodes. If so, firewall devices may be simulated by using the associatedcommunication manager module for a computing node to disallow orotherwise handle communications to and/or from the computing node in amanner consistent with one or more simulated firewall devices. Such nodecommunication manager modules may similarly simulate routers and subnetsby controlling how and whether intercommunications are passed betweencomputing nodes, and by responding to requests from computing nodes forinformation (e.g., ARP, or address resolution protocol, requests) withappropriate response information. One or more external communicationmanager modules of the CNS 105 may manage communications between thecomputing nodes provided by the CNS 105 and external computing systems,such as to similarly simulate firewall devices and enforce specifiednetwork access constraints, as well as to manage configured accessmechanisms for remote resource services and secure connections to remoteclient private computer networks. Other types of network topologyinformation may be similarly simulated, and additional details regardingthe use of various modules of the CNS 105 in some embodiments arediscussed below with respect to FIG. 2 and elsewhere.

In addition, in at least some embodiments, a client may interact withthe module 110 to configure various network access constraintinformation for a computer network provided for the client (e.g., viaone or more programmatic interactions with an API provided by the CNS105), and such network access constraint information may later bedynamically modified for a provided computer network in at least somesuch embodiments, such as after the provided computer network hasalready been in use by the client. For example, a client may specifyinformation about whether and how some or all of the computing nodes ofa provided computer network are allowed to communicate with othercomputing nodes of the provided computer network and/or with otherexternal computing systems, such as based on one or more of thefollowing: directions of communications (incoming versus outgoing);types of communications (e.g., based on the types of content includedand/or the types of communication protocols used, such as to allow HTTPrequests for text but not images and to not allow FTP requests);locations of other computing systems (e.g., whether part of the providedcomputer network, part of a remote client computer network correspondingto the provided computer network, part of a remote resource service towhich private or other specialized access has been established, externalto the provided computer network and any corresponding remote clientcomputer network, etc.); types of other computing systems; etc. Inaddition, as discussed in greater detail elsewhere, in at least someembodiments a provided computer network may be configured to provideprivate or other specialized access to one or more remote resourceservices, such as via a configured access mechanism that is part of orotherwise local to the provided computer network. In a manner similar tothat for network topology information and other routing information, theCNS 105 may enforce network access constraint information for providedcomputer networks in various manners. Additional details related tomanaging communications for provided computer networks in someembodiments are discussed below with respect to FIG. 2 and elsewhere.

FIG. 1B illustrates additional details regarding an example computernetwork 120 a that may be provided by the CNS 105 (or other embodimentof a configurable network service) for a client, with the providedcomputer network 120 a in this example being a private network extensionto a remote private computer network of the client, such as one of theremote private computer networks 130 of FIG. 1A. In this example,various connections and communication paths for the provided computernetwork 120 a are shown in a conceptual manner to illustrate types ofconfigurable network access constraints and network topology, and FIG. 2illustrates additional details regarding an example of underlyingsubstrate networks and connections that may be used to create providedcomputer networks such as the example provided computer network 120 a.

In particular, in FIG. 1B, the provided computer network 120 a includesvarious computing nodes provided by the CNS 105 that are located at afirst geographical location 1 160 (e.g., at a first data center at thegeographical location 1), with the various computing nodes beingconfigured into logical groups 164, 165 and 166 in this example (e.g.,to correspond to different subnets and/or associated configurednetworking devices, not shown). In this example, a single conceptualvirtual router 162 is shown at geographical location 1 to controlcommunications between those computing nodes and other computingsystems, so as to illustrate different types of communications that mayoccur, although the provided computer network 120 a may actually havemultiple or no configured networking devices at geographical location 1,and the computer network 120 a may be implemented by the configurablenetwork service at the geographical location 1 in various manners, suchas via multiple physical interconnected routers or other networkingdevices, by using an underlying substrate network and associated modulesthat control communications over the underlying substrate network, etc.In this example, the virtual router 162 operates in accordance with theconfigured information for the provided computer network 120 a,including configured network topology information, configured private orother specialized access to remote resource services, and otherconfigured network access constraint information, such as to routecommunications that are sent to network addresses within the providedcomputer network 120 a to corresponding destination computing nodes onthe provided computer network 120 a, and to route other communicationsto other network addresses outside of the provided computer network 120a as appropriate. Furthermore, communications that are not permitted byconfigured firewall devices, configured network topology information, orother configured network access constraints may be blocked or otherwisemanaged by the virtual router 162.

In this example, the computer network 120 a is provided for an exampleClient 1, and is a network extension to a remote computer network ofClient 1. Client 1's remote computer network includes multiple computingsystems (not shown) at a first remote location Site A 190, and thevirtual router 162 is configured to communicate with those multiplecomputing systems via a virtual communication link 170 at thegeographical location 1. For example, as discussed in greater detailelsewhere, the provided computer network 120 a may include one or moreconfigured VPN connections to the multiple computing systems at Site A190, and the communication link 170 may correspond to one or more suchVPN connections. In addition, the remote computer network of Client 1may optionally include computing systems at one or more other locations,such as the illustrated optional Site B 192, and if so the virtualrouter 162 may further be configured to communicate with those othercomputing systems at the other locations, such as via an optionalvirtual communication link 172 to Site B 192 (e.g., via one or moreother configured VPN connections directly to Site B). When multiple VPNconnections or other secure connections are used to remote computingsystems of a remote computer network, each connection may correspond toa subset of the remote computing systems (e.g., by being associated witha subset of the network addresses of the remote computer network thatcorrespond to those remote computing systems), so as to causecommunications to be routed to the appropriate connection. In otherembodiments, multiple VPN connections or other secure connections may beused to remote computing systems at one or more locations, but may eachsupport communications to any of the remote computing systems, such asif the multiple connections are redundant alternatives (e.g., used forload balancing). Furthermore, in some embodiments, a client's remotecomputer network may include multiple computing systems at multiplesites, but only a single VPN connection or other secure connection tothe remote computing systems may be used, with the remote computernetwork being responsible for routing the communications to theappropriate site and computing system.

In addition, the provided computer network 120 a may be configured toallow all, some or no communications between the computing nodes of theprovided computer network 120 a and other external computing systemsthat are generally accessible on the Internet 196 or other publicnetworks. If at least some such external communications are allowed, thevirtual router 162 may further be configured to communicate with thoseexternal multiple computing systems via an optional virtualcommunication link 178 of the provided computer network 120 a, such asin conjunction with an optional virtual border router 155 for theprovided computer network 120 a. The virtual border router 155 may bephysically implemented in various manners, such as by the CNS 105 usingone or more actual firewall devices or border router devices that managecommunications between external computing systems and the variouscomputing nodes provided by the CNS 105 at geographical location 1(e.g., actual devices that support numerous computer networks providedby the CNS 105 to clients that use those computing nodes of the CNS105), by using an underlying substrate network and associated modulesthat control communications over the underlying substrate network (e.g.,to prevent disallowed communications from being sent by computing nodesof the provided computer network 120 a onto the substrate network), etc.Furthermore, the virtual border router 155 may further conceptuallyassist in managing other communications to other computing systemsexternal to the provided computer network 120 a, such as to the remoteclient computer network at Sites A and B, to one or more remote resourceservices, etc.

In addition, the provided computer network 120 a may be configured toprovide private or other specialized access to one or more remoteresource services, such as by assigning one or more network addresses ofthe provided computer network 120 a to represent those one or moreremote resource services, and by optionally configuring particularactions to be taken for communications sent to those assigned networkaddresses. In this example, the virtual router 162 has been configuredto provide local access to remote resource service 194 via a virtualcommunication link 174 of the provided computer network 120 a. Thus, forexample, if one of the computing nodes of the provided computer network120 a sends a communication to a particular network address of theprovided computer network 120 a that is mapped to the communication link174, the virtual router may forward that communication to the remoteresource service 194 external to the provided computer network 120 a(e.g., via the Internet or other public networks). In other embodiments,the remote resource service 194 may implement an interface that is partof the CNS 105 or otherwise at the geographical location 1, and if sothe communications sent to the particular network address of theprovided computer network 120 a that is mapped to the communication link174 may instead be forwarded to that interface of the remote resourceservice for handling.

In addition, the virtual communication link 174 may be configured in atleast some embodiments to manage communications sent via the link invarious manners, such as to modify those communications in one or moremanners before they are forwarded to the remote resource service 194, orto otherwise access the remote resource service 194 in a specializedmanner. For example, in the illustrated embodiment, the virtualcommunication link 174 may be configured to correspond to a particularnamespace within the remote resource service 194, with a subset of thecomputing-related resources provided by the remote resource service 194being part of that namespace. Accordingly, the virtual communicationlink 174 may be configured to access resources within the particularnamespace, such as by modifying or translating communications to use aname or other identifier associated with the particular namespace, byusing a particular interface of the remote resource service thatsupports indicating a particular namespace, etc. In addition, if thevirtual communication link 174 is configured to correspond to aparticular namespace or to otherwise correspond to a subset of theresources provided by the remote resource service 194, the providedcomputer network 120 a may optionally be further configured to includeone or more other virtual communication links that also correspond tothe same remote resource service 194 but are configured to access theremote resource service 194 in other manners. For example, the providedcomputer network 120 a may optionally include a distinct virtualcommunication link 176 that is configured to access the remote resourceservice 194 in a distinct manner than that of virtual communication link174, such as to correspond to a distinct second namespace, to notcorrespond to any particular namespace, to use an identifier of acustomer of the remote resource service 194 that is distinct from acustomer identifier used for communication link 174, etc. In thisexample, the virtual communication links 174 and 176 are configured touse different identifiers (e.g., different namespace identifiers), whichare represented in this example as ID 1 and ID 2 for the links 174 and176, respectively. Thus, the computing nodes of the provided computernetwork 120 a may be able to access different types of functionalityfrom remote resource 194. Furthermore, while not illustrated here, theprovided computer network 120 a may be similarly configured to accessone or more other remote resource services (not shown) using othervirtual communication links to those other remote resource services.

In addition to or instead of configuring the virtual communication link174 to access a particular namespace of the remote resource service 194,the virtual communication link may be configured in at least someembodiments to provide additional information to the remote resourceservice 194 to allow the remote resource service 194 to validate thelocation or other source of the communications as being the providedcomputer network 120 a. For example, in the illustrated embodiment, thevirtual communication link 174 may be configured to correspond to one ormore particular identifiers or other access control indicators that areassociated with the provided computer network 120 a by the configurablenetwork service or by the remote resource service 194, so that a subsetof new and/or existing computing-related resources provided by theremote resource service 194 that are accessed via the virtualcommunication link 174 are associated with the access controlindicator(s), for use by the remote resource service 194 in restrictingaccess to those resources. Accordingly, the virtual communication link174 may be configured to use the specified additional indicator(s)associated with the provided computer network 120 a in various manners,such as to modify communications to include the additional indicator(s),to send the additional indicator(s) along with the communicationswithout modification of the communications, to use a particularinterface of the remote resource service that supports including suchadditional indicator(s), etc. In addition, if the virtual communicationlink 174 is configured to correspond to one or more additionalindicators, the provided computer network 120 a may optionally befurther configured to include one or more other virtual communicationlinks that also correspond to the same remote resource service 194 butare configured to access the remote resource service 194 in othermanners. For example, the provided computer network 120 a may optionallyconfigure the distinct virtual communication link 176 to access theremote resource service 194 without using any additional indicators(e.g., to provide the same access to the remote resource service 194 aswould otherwise be publicly available), to use one or more otheradditional access control indicators that are distinct from those usedwith virtual communication link 174, to use an identifier of a customerof the remote resource service 194 that is distinct from a customeridentifier used for virtual communication link 174, etc. Furthermore,while not illustrated here, the provided computer network 120 a may besimilarly configured to access one or more other remote resourceservices (not shown) using other virtual communication links to thoseother remote resource services, such as other virtual communicationlinks that are configured to use the same one or more additionalindicators as virtual communication link 174, or that are otherwiseconfigured.

In the illustrated embodiment, in addition to the computing nodes of theCNS 105 at geographical location 1, the provided computer network 120may further include computing nodes 184 provided by the CNS 105 that arelocated at a second geographical location 2 180 (e.g., at a distinctsecond data center at the geographical location 2). Accordingly, thevirtual router 162 may be configured to include an optional virtualcommunication link 168 to the portion of the provided computer network120 a at the geographical location 2. In this example, the portion ofthe provided computer network 120 a at the geographical location 2similarly is illustrated with a conceptual virtual router 182 to managecommunications to and from the computing nodes 184, including tocommunicate with the portion of the provided computer network 120 at thegeographical location 1 via a virtual communication link 188. Suchcommunications between computing nodes of the CNS 105 at differentgeographical locations may be handled in various manners in variousembodiments, such as by sending the communications over the Internet orother public networks (e.g., as part of a secure tunnel, such as thatuses encryption supported by the CNS 105), by sending the communicationsin a private secure manner (e.g., via a dedicated lease line between thegeographical locations), etc. In addition, while not illustrated here,the portion of the provided computer network 120 a at the geographicallocation 2 may similarly include some or all of the same types of othervirtual communication links illustrated for the portion at geographicallocation 1, such as to a remote client private network (e.g., via one ormore VPN connections distinct from any VPN connections to thegeographical location 1), to remote resource services, to the Internet,etc.

It will be appreciated that the example provided computer network 120 aof FIG. 1B is included for exemplary purposes, and that other computernetworks provided by the CNS 105 for clients may not include all of thetypes of configured communications links and network topologyinformation, and/or may include other types of configured communicationslinks and network topology information that is not illustrated here. Forexample, in some embodiments and situations, a provided computer networkmay include configured devices and other resources in addition to orinstead of computing nodes, and if so, each such other resource mayoptionally be assigned a network address of the provided computernetwork. Furthermore, the conceptual devices and communication linksillustrated in FIG. 1B may be implemented using a variety of types ofunderlying physical devices, connections and modules. In addition, whilenot illustrated here, clients may perform a variety of other types ofinteractions with remote resource services, whether from providedcomputer networks or instead other remote computing systems, such as tosubscribe/register to use resource, receive/create various credentials(e.g., user IDs, passwords, etc.), create resources and/or namespacesfrom other remote computing systems (e.g., that are part of a remoteprivate corporate network) that are later accessed from a providedcomputer network (e.g., a network extension to the private corporatenetwork), etc.

FIG. 2 is a network diagram illustrating an example embodiment ofcomputing systems for use in providing computer networks, such as by anembodiment of a configurable network service. In particular, in thisexample, a number of physical computing systems are co-located in a datacenter 200 and are interconnected via various networking devices and oneor more physical networks. The physical computing systems and otherdevices are used in this example by a configurable network service toprovide multiple computer networks for clients, by establishing andmaintaining each of the provided computer networks as a virtual network,and by using the physical network(s) as a substrate network on which thevirtual networks are overlaid. For example, with respect to the exampleof FIG. 1B, the data center 200 may be located at geographical location1, and the illustrated physical computing systems may be used to providethe computing nodes 164, 165 and 166 of provided computer network 120 a.The use of the overlay networks and underlying substrate network may betransparent to the computing nodes of the provided computer networks inat least some embodiments.

Thus, in this example, the computer networks provided by theconfigurable network service are implemented as virtual overlay networksthat send communications via an underlying physical substrate network.The provided virtual overlay networks may be implemented in various waysin various embodiments, such as without encapsulating communications insome embodiments (e.g., by embedding virtual network address informationfor a virtual network in communications configured for a networkingprotocol of the physical substrate network). As one illustrativeexample, a virtual network may be implemented using 32-bit IPv4(“Internet Protocol version 4”) network addresses, and those 32-bitvirtual network addresses may be embedded as part of 128-bit IPv6(“Internet Protocol version 6”) network addresses used by the physicalsubstrate network, such as by re-headering communication packets orother data transmissions (e.g., using Stateless IP/ICMP Translation, orSIIT), or otherwise modifying such data transmissions to translate themfrom a first networking protocol for which they are configured to adistinct second networking protocol. As another illustrative example,both the virtual network and substrate network may be implemented usingthe same network addressing protocol (e.g., IPv4 or IPv6), and datatransmissions sent via the provided virtual overlay network usingvirtual network addresses may be modified to use different physicalnetwork addresses corresponding to the substrate network while thetransmissions are sent over the substrate network, but with the originalvirtual network addresses being stored in the modified datatransmissions or otherwise tracked so that the data transmissions may berestored to their original form when they exit the substrate network. Inother embodiments, at least some of the overlay networks may beimplemented using encapsulation of communications.

The illustrated example of FIG. 2 includes a data center 200 withmultiple physical computing systems operated by an embodiment of theconfigurable network service. The data center 200 is connected to one ormore public networks 235 external to the data center 200, which provideaccess to one or more remote computing systems 245 a via private network240, to one or more other globally accessible data centers 260 that eachhave multiple computing systems at other geographical locations, and toone or more other remote computing systems 245 b. The public network 235may be, for example, a publicly accessible network of networks, possiblyoperated by various distinct parties, such as the Internet, and theprivate network 240 may be, for example, a corporate network that iswholly or partially inaccessible from computing systems external to theprivate network 240. Computing systems 245 b may each be, for example, ahome computing system that connects directly to the Internet (e.g., viaa telephone line, cable modem, a Digital Subscriber Line (“DSL”), etc.)

In this example, the configuring of the virtual provided computernetworks is facilitated by a manager module 210 of the configurablenetwork service, and multiple other modules of the configurable networkservice are used to implement functionality of the provided computernetworks, such as from the edge of the physical substrate network bymodifying communications that enter and/or leave the substrate network.In particular, in this example, multiple node communication managermodules of the configurable network service each manage communicationsto and from associated computing nodes, such as the illustrated nodecommunication manager modules 209 a, 209 d and 250 as discussed ingreater detail below. In addition, in this example, an externalcommunication manager module 270 of the configurable network servicemanages communications between the physical computing systems within thedata center 200 and external computing systems, as discussed in greaterdetail below. While only a single external communication manager module270 is illustrated in this example, it will be appreciated that thefunctionality of the module 270 may be implemented using multipledevices, such as for redundancy and load balancing.

The data center 200 includes a number of physical computing systems 205a-205 d and 255 a-255 n, as well as a CNS node communication managermodule 250 that executes on one or more other computing systems (notshown) to manage communications for the associated computing systems 255a-255 n, and a manager module 210 of the configurable network servicethat executes on one or more computing systems (not shown). In thisexample embodiment, each physical computing system 205 a-205 d hostsmultiple virtual machine computing nodes and also includes a virtualmachine (“VM”) node communication manager module (e.g., as part of avirtual machine hypervisor monitor for the physical computing system),such as the CNS VM node communication manager module 209 a and virtualmachines 207 a on computing system 205 a, and such as CNS VM nodecommunication manager module 209 d and virtual machines 207 d oncomputing system 205 d. Each of the virtual machine computing nodes maybe used by the configurable network service as a distinct computing nodeof a computer network provided for a client. Physical computing systems255 a-255 n do not execute any virtual machines in this example, andthus may each act as a distinct computing node that is part of acomputer network provided for a client by the configurable networkservice. In other embodiments, all or none of the physical computingsystems at the data center may host virtual machines.

This example data center further includes multiple physical networkingdevices, such as switches 215 a and 215 b, edge routers 225 a-225 c, andcore routers 230 a-230 c. Switch 215 a is part of a physical networkthat includes physical computing systems 205 a-205 c, and is connectedto edge router 225 a. Switch 215 b is part of a distinct physicalnetwork that includes physical computing systems 205 d, 255 a-255 n, andthe computing system(s) providing the CNS node communication managermodule 250 and the CNS system manager module 210, and is connected toedge router 225 b. The physical networks established by switches 215a-215 b, in turn, are connected to each other and other networks (e.g.,the public network 235) via an intermediate interconnection network 220,which includes the edge routers 225 a-225 c and the core routers 230a-230 c. The edge routers 225 a-225 c provide gateways between two ormore networks. For example, edge router 225 a provides a gateway betweenthe physical network established by switch 215 a and the interconnectionnetwork 220. Edge router 225 c provides a gateway between theinterconnection network 220 and public network 235. The core routers 230a-230 c manage communications within the interconnection network 220,such as by forwarding packets or other data transmissions as appropriatebased on characteristics of such data transmissions (e.g., headerinformation including source and/or destination substrate networkaddresses, protocol identifiers, etc.) and/or the characteristics of theinterconnection network 220 itself (e.g., routes based on physicalnetwork topology, etc.).

The illustrated node communication manager modules manage communicationssent to and from associated computing nodes. For example, nodecommunication manager module 209 a manages associated virtual machinecomputing nodes 207 a, node communication manager module 209 d managesassociated virtual machine computing nodes 207 d, and each of the othernode communication manager modules may similarly manage communicationsfor a group of one or more other associated computing nodes. Theillustrated node communication manager modules may manage communicationsbetween computing nodes so as to overlay a particular virtual networkover the intermediate physical substrate network (e.g., theinterconnection network 220 and the physical networks associated withswitches 215 a and 215 b), and may implement firewall policies and othernetwork access constraints to control such communications. The externalcommunication manager module 270 manages external communications thatenter and leave the data center 200, such as to further implement theoverlay networks over the substrate network within the data center 200with regard to such external communications. The external communicationmanager module 270 may take actions to implement firewall policies andother network access constraints, including at least some configuredaccess mechanisms for provided computer networks that allow private orother specialized access to remote resource services external to thedata center 200, and optionally at least some VPN connections toexternal remote client computer networks, or may instead operate inconjunction with other hardware and/or software (not shown) thatimplements the configurable network service's portion of such VPNconnections.

Thus, as one illustrative example, one of the virtual machine computingnodes 207 a on computing system 205 a may be part of a particularprovided virtual computer network (e.g., provided computer network 120 aof FIG. 1B) for a client, along with one of the virtual machinecomputing nodes 207 d on computing system 205 d and with the computingsystem 255 a (and optionally other computing nodes in this data centeror in one or more other data centers 260 that are also used by theconfigurable network service), and with IPv4 being used to represent thevirtual network addresses for the virtual network. Other of the virtualmachine computing nodes 207 a, virtual machine computing nodes 207 d,and computing systems 255 b-255 n (as well as other of the illustratedcomputing nodes) may be currently dedicated to other computer networksbeing provided to other clients, may be currently unassigned to aprovided computer network and available for use by the configurablenetwork service, and/or may also be part of the same particular providedvirtual computer network. A program executing for the client on thevirtual machine computing node 207 a that is part of the particularprovided virtual computer network may then direct an outgoingcommunication (not shown) to the virtual machine computing node 207 d ofthe particular provided virtual computer network, such as by specifyinga virtual network address for that provided virtual computer networkthat is assigned to that destination virtual machine computing node 207d. The node communication manager module 209 a receives the outgoingcommunication, and in at least some embodiments determines whether toauthorize the sending of the outgoing communication, such as based onpreviously configured information about the sending virtual machinecomputing node 207 a and/or about the destination virtual machinecomputing node 207 d, and/or by dynamically interacting with the systemmanager module 210 (e.g., to obtain an authorization determination, toobtain some or all such information, etc.).

If the node communication manager module 209 a determines that theoutgoing communication is authorized (or does not perform such anauthorization determination), the module 209 a determines the actualphysical substrate network location corresponding to the destinationvirtual network address for the communication. In this example, theinterconnection network uses IPv6 to represent the actual networkaddresses for computing nodes connected via the interconnection network,and the module 209 a re-headers the outgoing communication so that it isdirected to node communication manager module 209 d using an actual IPv6substrate network address. The node communication manager module 209 amay determine the actual IPv6 destination network address to use for thevirtual network address of the destination virtual computing node 207 dby, for example, dynamically interacting with the system manager module210, or may have previously determined and stored that information(e.g., in response to a prior request from the sending virtual machinecomputing node 207 a for information about that destination virtualnetwork address, such as a request using Address Resolution Protocol, orARP). In this example, the actual IPv6 destination network address thatis used embeds the virtual destination network address and additionalinformation, so as to send the communication over the overlay networkwithout encapsulation.

When the node communication manager module 209 d receives thecommunication via the interconnection network 220, it extracts thevirtual destination network address and additional information from theactual IPv6 destination network address, and determines to which of thevirtual machine computing nodes 207 d that the communication isdirected. The node communication manager module 209 d next optionallydetermines whether the communication is authorized for the destinationvirtual machine computing node 207 d, such as by extracting the virtualsource network address and additional information from the actual IPv6source network address, and confirming that the computing node with thatvirtual source network address is actually managed by the nodecommunication manager module that forwarded the communication (in thisexample, node communication manager module 209 a), so as to preventspoofing of source network addresses by malicious senders. If thecommunication is determined to be authorized (or the node communicationmanager module 209 d does not perform such an authorizationdetermination), the module 209 d then re-headers the incomingcommunication so that it is directed to the destination virtual machinecomputing node 207 d using an appropriate IPv4 network address for thevirtual network, such as by using the sending virtual machine computingnode's virtual network address as the source network address and byusing the destination virtual machine computing node's virtual networkaddress as the destination network address. After re-headering theincoming communication, the module 209 d then forwards the modifiedcommunication to the destination virtual machine computing node. In atleast some embodiments, before forwarding the incoming communication tothe destination virtual machine, the module 209 d may also performadditional steps related to security. For example, the module 209 d mayverify that the sending virtual machine computing node is authorized tocommunicate with the destination virtual machine (e.g., based onbelonging to the same virtual network and/or on network accessconstraint information specified for that provided virtual network,being associated with the same customer or other entity, beingassociated with different entities whose computing nodes are authorizedto intercommunicate, etc.) and/or that the incoming communication is ofan allowed type, such as based on information previously obtained by themodule 209 d or based on interacting with the system manager module 210.

If the sending virtual machine computing node 207 a instead (or inaddition) directs an outgoing communication (not shown) to one or moreintended destination computing systems external to the data center 200,the node communication manager module 209 a receives and handles theoutgoing communication in a similar manner. An intended externaldestination computing system may be, for example, another computing nodethat is part of the same particular provided virtual computer network(e.g., on a remote virtual client computer network for which theparticular provided computer network is an extension, or at another datacenter 260 that is also used by the configurable network service toprovide a portion of the particular virtual computer network), acomputing system of a remote resource service, a computing system thatis publicly accessible on the Internet, etc. In at least someembodiments and situations, the module 209 a may first determine whetherto authorize the sending of the outgoing communication, and if sodetermines the actual physical substrate network location correspondingto the destination network address for the communication. In thisexample, the determined physical substrate network location correspondsto the external communication manager module 270, such as if the module270 is associated with all virtual and/or actual network addresses thatare not otherwise assigned to node communication manager modules. Whenthe module 270 receives the communication via the interconnectionnetwork 220, it similarly extracts the destination network address andadditional information from the received communication, and determineswhether and how to forward the communication, including optionallydetermining whether the communication is authorized for the intendeddestination. If the communication is determined to be authorized (or themodule 270 does not perform such an authorization determination), themodule 270 then re-headers the incoming communication so that it isdirected to the destination using an appropriate IPv4 public networkaddress (or other network address appropriate for the public network235), and then forwards the modified communication over the publicnetwork 235.

Thus, as noted above, the external communication manager module 270handles outgoing communications from provided computer networks in theillustrated embodiment, including outgoing communications sent to remoteresource services via configured access mechanisms for those remoteresource services. If the outgoing communication is being sent to aremote resource service via a configured access mechanism for theparticular provided computer network, the module 270 and/or the sendingcomputing node's associated node communication manager module may takefurther actions in at least some embodiments and situations. Forexample, the particular provided virtual computer network may have aconfigured access mechanism for a particular remote resource service(e.g., a remote resource service provided via one or more of thecomputing systems 245 b or via one or more computing systems at anotherdata center 260) that is mapped to a particular namespace of that remoteresource service, and the sending virtual machine computing node 207 amay send the communication via that configured access mechanism. Theconfigured access mechanism to that remote resource service for theparticular provided computer network may be, for example, a virtualnetwork address of the particular provided computer network that isassigned to represent that configured access mechanism, and if so thatassigned virtual network address may be associated with the module 270to cause the outgoing communication to be directed to the module 270.Before forwarding such an outgoing communication to the remote resourceservice via the public network 235, the module 270 may take variousactions to reflect the configuration for the access mechanism used, suchas to modify the outgoing communication to reference or otherwise usethe particular namespace to which the access mechanism corresponds. Insuch situations, the module 270 may determine the namespace and otherconfiguration information for the access mechanism in various ways, suchas by storing the configuration information locally, contacting thesystem manager module 210 to obtain the configuration information, etc.In addition, the module 270 may determine how and when to modifycommunications to use the particular namespace in various manners, suchas by the remote resource service having previously providedcorresponding configuration information to the configurable networkservice (e.g., an indication of one or more particular messageparameters that indicate a namespace; an indication of one or moreparticular message parameters used to name or reference resources, whichmay optionally include a namespace identifier; an indication of types ofmessages that allow a namespace to be indicated or that otherwise usenamespace information; etc.).

As one particular illustrative example, the remote resource service mayprovide data storage services, and the outgoing communication may be arequest to access a particular storage-related resource (e.g., toretrieve a stored object or other group of stored data). If so, theparticular storage resource may have been previously created by theclient as part of a namespace defined by the client, such as by using acomputing system external to the provided computer network (e.g., on aremote private computer network of the client. By configuring the accessmechanism for the particular provided computer network to use that samenamespace, the computing nodes of the provided computer network mayaccess and use existing stored resources of the client. As anillustrative example, if the remote private computer network of theclient is a corporate network, the client may use different namespacesto store different types of data, such as to store sensitive humanresources data in a first namespace, to store restricted softwaredevelopment software and other data in a second namespace, and to storeother corporate data that is generally available throughout thecorporation via a third namespace. If the provided computer network ofthe configurable network service is used by only a particular subset ofthe corporation (e.g., human resource personnel), the access mechanismto the remote resource service for the particular provided computernetwork may be configured to use the first namespace for the sensitivehuman resources data. Furthermore, the particular provided computernetwork may optionally have a second access mechanism configured to theremote resource service (e.g., using a different assigned virtualnetwork address of the provided computer network), such as to use thethird namespace for the generally available corporate data, so that thecomputing nodes of the particular provided computer network may interactwith different local virtual network addresses of the particularprovided computer network to obtain access to different groups ofresources.

As another illustrative example, the access mechanism to the remoteresource service for the particular provided computer network mayinstead be configured to allow only computing nodes of the particularprovided computer network to have access to storage resources that arecreated and used by those computing nodes. If so, the configurablenetwork service may determine a new namespace to use with the particularprovided computer network, such as by automatically generating a newnamespace (e.g., without providing that information to the computingnodes of the particular provided computer network) or by using a newnamespace that is indicated by the client with the configurationinformation, and may configure the access mechanism to use the newnamespace. The configurable network service or a computing node of theparticular provided computer network may further need to take initialaction to create the new namespace within the remote resource service,depending on the remote resource service. Once the new namespace isavailable, the computing nodes of the particular provided computernetwork may similarly use the configured access mechanism to interactwith the remote resource service to create new stored resources that arepart of the new namespace and to access such stored resources, and theexternal communication manager module 270 will similarly modify theoutgoing communications as appropriate to use the new namespace.

In addition to or instead of being configured to implement a configuredaccess mechanism corresponding to a particular namespace within aparticular remote resource service, the external communication managermodule 270 may in some embodiments be configured to include one or moreadditional indicators related to access control for some or allcommunications sent to that remote resource service via that accessmechanism, and the sending virtual machine computing node 207 a may sendsuch a communication via that configured access mechanism. Beforeforwarding such an outgoing communication to the remote resource servicevia the public network 235, the module 270 may take various actions toreflect the configuration for the access mechanism used, such as tomodify the outgoing communication to include the one or more additionalindicators to which the access mechanism corresponds, such as bymodifying the header and/or body of the communication in a mannerspecific to the remote resource service (e.g., if the remote resourceservice allows client specification of one or more access controlindicators, to include the one or more additional indicators in a mannersupported by the remote resource service, whether instead of or inaddition to any indicators specified by the sending virtual machinecomputing nodes 207 a). In such situations, the module 270 may determinethe additional indicator(s) for the access mechanism in various ways,such as by storing the information locally, contacting the systemmanager module 210 to obtain the information, etc. In addition, themodule 270 may determine how and when to modify communications to usethe particular additional indicator(s) in various manners, such as bythe remote resource service having previously provided correspondingconfiguration information to the configurable network service (e.g., anindication of one or more particular message parameters that indicatesuch access control indicators; an indication of one or more particularmessage parameters used to access resources, which may optionallyinclude one or more such access control indicators; an indication oftypes of messages that allow one or more such access control indicatorsto be specified or that otherwise use such access control indicators;etc.).

In a manner similar to the examples previously discussed with respect tothe use of namespace information with the configured access mechanism,the remote resource service may provide data storage services, and theoutgoing communication may be a request to access a particularstorage-related resource (e.g., to retrieve a stored object or othergroup of stored data). If so, the particular storage resource may havebeen previously created by one of the computing nodes of the providedcomputer network to which the sending virtual machine computing node 207a belongs, or may be being newly created or accessed as part of thecurrent communication. In some embodiments, the configurable networkservice may further need to take initial action to specify the one ormore additional indicators for use within the remote resource service(e.g., to define them), depending on the remote resource service. Asdiscussed in greater detail elsewhere, the sending virtual machinecomputing node 207 a and the associated client may be unaware of the useof the additional indicator(s), but the external communication managermodule 270 will nonetheless modify the outgoing communications asappropriate to use the associated indicator(s).

Furthermore, as noted above, the external communication manager module270 handles outgoing communications in the illustrated embodiment thatare from provided computer network extensions to remote computernetworks to which the extensions correspond, such as outgoingcommunications sent via a configured VPN connection to a particularremote computer network. In at least some embodiments, the configurablenetwork service provides a remote access establishment API that allows aclient to programmatically initiate the establishment of such a VPNconnection from a location remote to the data center 200 to the computernetwork provided for the client at the data center 200, such as to causeappropriate hardware devices, software and/or configuration informationto be delivered to the remote location for use by the client inestablishing the VPN connection. For example, one of the computingsystems 245 b may correspond to an online retailer that sells orotherwise provides such hardware devices and/or software, and if so theconfigurable network service may use a separate API provided by theretailer to place an order for such hardware devices and/or software fordelivery to the remote location or other designated locationcorresponding to the client (e.g., as specified by the client as part ofinvoking the provided API of the configurable network service, based oninformation previously stored by the configurable network service forthe client, based on information previously stored by the retailer forthe client, etc.). Once such a VPN connection or other secure connectionis established to allow the client to have remote access to the providedcomputer network, the module 270 may further take actions to support thesecure connection, such as by using the secure connection to send anoutgoing communication that is intended for one or more destinationcomputing systems at the remote location to which the secure connectioncorresponds.

Thus, as described above with respect to FIG. 2, in at least someembodiments, the configurable network service provides virtual computernetworks to clients by implementing them as overlay networks using anunderlying substrate network, such as using various node communicationmanager modules of the configurable network service and one or moreexternal communication manager modules of the configurable networkservice. In at least some embodiments, one or more system managermodules may further facilitate configuring communications betweencomputing nodes, such as by tracking and/or managing which computingnodes belong to which provided virtual networks, and by providinginformation about actual physical substrate network addresses thatcorrespond to virtual network addresses used for a particular virtualnetwork (e.g., by a particular customer or other entity). In addition, asystem manager module may receive an indication of a virtual machinecomputing node on a target physical computing system and of a providedvirtual network to which the virtual machine is to be associated, andthen initiate configuration of a virtual machine node communicationmanager module for the target physical computing system so as toassociate the virtual machine with the virtual network, or the nodecommunication manager module may instead initiate that configuration(e.g., when the virtual machine first initiates or receives acommunication).

In at least some embodiments, detection and/or prevention ofunauthorized communications may be based at least in part on a topologyof the one or more intermediate substrate networks on which a virtualnetwork is overlaid, as previously noted. In such embodiments, thephysical network address used for such a computing node forcommunications over the substrate network includes an indication of thecomputing node's virtual network address, and includes a partial networkaddress for the substrate network that corresponds to a location of thecomputing node's associated node communication manager module (e.g., asub-network or other portion of the substrate network for which the nodecommunication manager module manages communications). Thus, in order fora malicious user to correctly construct a valid physical network addressfor a computing node that is part of a virtual network, the malicioususer would need to gain access to information about the virtual networkto which the computing node belongs, to gain access to information aboutthe topology of the computing node's physical substrate network locationin order to determine the partial network address for the associatednode communication manager module, and to determine how to use thatinformation to construct the physical network address. The validity ofconstructed physical network addresses may be checked in various ways,such as by identifying a computing node to which a virtual addressembedded in a constructed physical network address corresponds, andverifying that a location of that identified computing node correspondsto one of the computing nodes in the portion of the substrate networkthat corresponds to the partial network address (e.g., one of thecomputing nodes managed by a node communication manager module to whichthe partial network address corresponds). In addition, the validity ofconstructed physical network addresses may be checked at various times,such as by a node communication manager module that receives an incomingcommunication intended for a destination computing node (e.g., to verifythat the source physical network address is valid), by a manager modulethat receives a message purportedly from a node communication managermodule on behalf of an indicated managed computing node (e.g., a messageto request a physical network address for an intended destinationcomputing node of interest), etc.

FIGS. 4, 5 and 6 provide additional details related to actions of thesystem manager module 210, node communication manager modules, andexternal communication manager module 270, respectively, in at leastsome embodiments. Furthermore, additional details related toimplementing overlay networks that may be used in at least someembodiments are included in U.S. application Ser. No. 12/060,074(Attorney Docket Number 120137.576), filed Mar. 31, 2008 and entitled“Configuring Communications Between Computing Nodes;” which isincorporated herein by reference in its entirety.

FIG. 3 is a block diagram illustrating example computing systemssuitable for executing an embodiment of a system for providing computernetworks for use by remote clients. In particular, FIG. 3 illustrates aserver computing system 300 suitable for executing an embodiment of aconfigurable network service system manager module that assists inproviding a configurable network service, as well as various clientcomputing systems 350, host computing systems 360, and other computingsystems 380. While not illustrated here, in some embodiments at leastsome of the illustrated computing systems may be co-located or otherwiseassociated (e.g., the server computing system 300 and at least some ofthe host computing systems 360 that are part of the configurable networkservice), such as at a data center, as described in greater detail withrespect to FIGS. 1B and 2. In addition, while not illustrated here,various other modules of the configurable network service may be presentand used in at least some embodiments, such as various nodecommunication manager modules and one or more external communicationmanager modules.

In the illustrated embodiment, the server computing system 300 hascomponents that include a CPU 305, various I/O components 310, storage320, and memory 330. The illustrated I/O components include a display311, a network connection 312, a computer-readable media drive 313, andother I/O devices 315 (e.g., a keyboard, a mouse, speakers, etc.). Inaddition, the illustrated client computing systems 350 have componentssimilar to those of server computing system 300, including a CPU 351,I/O components 352, storage 354, and memory 357. The other computingsystems 360 and 380 may also each include similar components to some orall of the components illustrated with respect to server computingsystem 300, but such components are not illustrated in this example forthe sake of brevity.

An embodiment of a Configurable Network Service (“CNS”) Manager module340 is executing in memory 330, and it interacts with computing systems350, 360 and 380 over one or more networks 390 (e.g., via the Internetand/or the World Wide Web, via a private cellular network, via a privatesubstrate network in use by the configurable network service, etc.). Inthis example embodiment, the module 340 includes functionality relatedto providing and managing computer networks for use by various clients(not shown) as part of a configurable network service, with the clientsusing computing systems 350 to configure and access the providedcomputer networks. The host computing systems 360 may also assist inproviding the configurable network service, such as by providingcomputing nodes for the computer networks provided by the configurablenetwork service. Similarly, in at least some embodiments, at least someof the other computing system 380 may also assist in providing theconfigurable network service, such as by facilitatingintercommunications between provided computer networks and externalremote computing systems (e.g., by implementing VPN connections or otheraccess mechanisms), by providing remote resource services that theprovided computer networks are configured to access, by facilitatingintercommunications between computing nodes of provided computernetworks (e.g., by implementing portions of a substrate network or otherinfrastructure of the configurable network service that facilitates thecommunications), etc.

The other computing systems 350, 360 and 380 may be executing varioussoftware as part of interactions with the module 340. For example, someor all of the client computing systems 350 may each be executingsoftware in memory 357 to interact with module 340 (e.g., as part of aWeb browser or specialized client-side application program), such as toenable a user of a client computing system to create and configure acomputer network for use by the user or other client of the configurablenetwork service. Furthermore, some or all of the client computingsystems 350 and/or other computing systems 380 may each be executingsoftware in memory 357 to interact on behalf of a client with a computernetwork being provided by the configurable network service for theclient, such as via a VPN connection that connects multiple of theclient computing systems 350 and/or other computing systems 380 that arepart of a remote network for a client to multiple of the host computingsystems 360 that provide computing nodes as part of a provided computernetwork extension for the client's remote network. In addition, one ormore users of the client computing systems 350 may interact with module340 to perform various other types of actions (e.g., administrativefunctions related to accounts of clients with the configurable networkservice, to monitor use of provided computer networks, etc.), asdiscussed in greater detail elsewhere. Furthermore, some of the hostcomputing systems 360 and/or the other computing systems 380 may executesoftware modules (not shown) to assist in providing the configurablenetwork service, such as node communication manager modules that assistin managing communications sent to and from computing nodes of providedcomputer networks. In addition, other of the computing systems 360 and380 may perform other functions, such as to execute remote resourceservices available to various users. Various information related to thefunctionality of module 340 and the configurable network service mayalso be stored in storage 320, such as information 322, and may includeinformation related to configuration and/or provision of computernetworks on behalf of multiple clients.

After the module 340 receives one or more requests (or otherindications) to create and configure a computer network for a client,the module 340 may perform various actions as discussed in greaterdetail elsewhere. Such actions may including selecting one or morecomputing nodes from the host computing systems 360 that will be part ofthe computer network, configuring those host computing systems and/orother computing systems to provide that computer network, and initiatingaccess of the provided computer network to remote computing systems 350or remote other computing systems 380 of a client. In addition, themodule 340 may further interact with computing systems 360 to managecomputer networks being provided, such as in response to requests fromclients or instead as automatically determined, including in somesituations to increase or decrease the quantity of computing nodes thatare part of a provided computer network, to modify configured networktopology for a provided computer network, to modify particular hostcomputing systems that provide computing nodes of the provided computernetwork (e.g., by migrating programs executing on one or more computingnodes of a provided computer network to other computing nodes), etc. Inaddition, the module 340 may monitor or otherwise interact with one ormore of the host computing systems 360 to track use and operation of theprovided computer networks.

It will be appreciated that computing systems 300, 350, 360 and 380 aremerely illustrative and are not intended to limit the scope of thepresent invention. The computing systems and/or computing nodes mayinstead each include multiple interacting computing systems or devices,and the computing systems/nodes may be connected to other devices thatare not illustrated, including through one or more networks such as theInternet, via the Web, or via private networks (e.g., mobilecommunication networks, etc.). More generally, a computing node or othercomputing system may comprise any combination of hardware or softwarethat may interact and perform the described types of functionality,including without limitation desktop or other computers, databaseservers, network storage devices and other network devices, PDAs,cellphones, wireless phones, pagers, electronic organizers, Internetappliances, television-based systems (e.g., using set-top boxes and/orpersonal/digital video recorders), and various other consumer productsthat include appropriate communication capabilities. In addition, thefunctionality provided by the illustrated module 340 may in someembodiments be distributed in additional modules, or the module 340 mayincorporate functionality described elsewhere as being provided bymultiple modules of the configurable network service (e.g., one or moresystem manager modules, one or more node communication manager modules,and one or more external communication manager modules). Similarly, insome embodiments, some of the functionality of the module 340 may not beprovided and/or other additional functionality may be available.

It will also be appreciated that, while various items are illustrated asbeing stored in memory or on storage while being used, these items orportions of them may be transferred between memory and other storagedevices for purposes of memory management and data integrity.Alternatively, in other embodiments, some or all of the software modulesand/or systems may execute in memory on another device and communicatewith the illustrated computing systems via inter-computer communication.Furthermore, in some embodiments, some or all of the systems and/ormodules may be implemented or provided in other manners, such as atleast partially in firmware and/or hardware, including, but not limitedto, one or more application-specific integrated circuits (ASICs),standard integrated circuits, controllers (e.g., by executingappropriate instructions, and including microcontrollers and/or embeddedcontrollers), field-programmable gate arrays (FPGAs), complexprogrammable logic devices (CPLDs), etc. Some or all of the modules,systems and data structures may also be stored (e.g., as softwareinstructions or structured data) on a computer-readable medium, such asa hard disk, a memory, a network, or a portable media article to be readby an appropriate drive or via an appropriate connection. The systems,modules and data structures may also be transmitted as generated datasignals (e.g., as part of a carrier wave or other analog or digitalpropagated signal) on a variety of computer-readable transmissionmediums, including wireless-based and wired/cable-based mediums, and maytake a variety of forms (e.g., as part of a single or multiplexed analogsignal, or as multiple discrete digital packets or frames). Suchcomputer program products may also take other forms in otherembodiments. Accordingly, the present invention may be practiced withother computer system configurations.

FIGS. 4A and 4B illustrate a flow diagram of an example embodiment of aConfigurable Network Service Manager routine 400. The routine may beprovided by, for example, execution of the system manager module 110 ofFIG. 1A, the system manager module 210 of FIG. 2, and/or the systemmanager module 340 of FIG. 3, such as to assist in managing operationsof a configurable network service that provides computer networks toremote clients. In the illustrated embodiment, at least some of thecomputer networks that are created and provided by the routine 400 maybe extensions to existing remote networks of clients, while in otherembodiments the networks that are created and provided by the routine400 may instead be standalone networks for use by clients that are notextensions of other networks.

The illustrated embodiment of the routine begins at block 405, where anindication is received of a message from a client or other informationthat is received. In at least some embodiments, the configurable networkservice that the routine 400 supports provides one or more APIs to allowremote clients to programmatically interact with the configurablenetwork service, and if so some or all of the indications received inblock 405 may be made via invocations or other programmatic interactionsof remote clients with those APIs, while in other embodiments andsituations, some or of the indications received in block 405 may insteadbe initiated by remote clients or others in other manners.

After block 405, the routine continues to block 410 to determine whetherthe indication received in block 405 is to initiate the creation of anew computer network to be provided on behalf of a requesting client,such as an extension to an existing remote network of the client. If so,the routine continues to block 415 to perform various actions to createthe new computer network extension or other new computer network onbehalf of the client. For example, as described in greater detailelsewhere, the received communication to create the new computer networkmay include various configuration information related to the computernetwork to be created, such as a number of computing nodes that are tobe part of the created computer network, an indication of whether thenew computer network is an extension to another remote network, etc. Theactions taken in block 415 may include, for example, selectingparticular computing nodes that are available from the configurablenetwork service for use in the new computer network that is beingcreated; generating and associating a unique identifier with the newcomputer network that is being created; storing any receivedconfiguration information for later use; etc. As described in greaterdetail elsewhere, such computing nodes may be selected from a group ofavailable computing nodes in various manners in various embodiments,such as based on capabilities of the selected computing nodes, based onnetwork locations of the selected computing nodes (e.g., on anunderlying substrate network of the configurable network service, on arelative network location to other computing nodes of the computernetwork, etc.), based on geographic locations of the selected computingnodes (e.g., in one of multiple geographically distributed data centers,on a relative geographic location to other computing nodes of thecomputer network, etc.), in a random manner, etc. Furthermore, while notillustrated here, the routine may provide to the client the uniqueidentifier for the new computer network or other reference for the newcomputer network, so as to allow the client to later reference the newcomputer network when performing further configuration of the newcomputer network.

After block 415, or if it is instead determined in block 410 that theindication received in block 405 is not to create a new computernetwork, the routine continues to block 420 to determine whether theindication received in block 405 includes information related to accessconstraints or other access information for an indicated computernetwork. For example, in some situations, a client may supply one ormore requests or other messages that are received and processed togetherwith respect to block 405, such as a request to create a new computernetwork extension and various specified configuration information forthat new computer network extension—if so, the indicated computernetwork for which access information is supplied may be the new computernetwork extension that was just created with respect to block 415. Inother situations and embodiments, a remote client may instead supplydifferent communications at different times that are received andprocessed with respect to block 405, such as an initial request tocreate a new computer network, and later one or more other separaterequests to specify various types of configuration information for thatpreviously created computer network. If it is determined in block 420that access information is received in block 405, the routine continuesto block 422 to determine whether the client has invoked a remote accessestablishment API or otherwise requested that remote access beestablished from a remote location of the client to the indicatedcomputer network, which in the illustrated embodiment is performed byinitiating the creation of a VPN connection to the indicated computernetwork from one or more remote computing systems of the client at theremote location. If so, the routine continues to block 425 to execute aVPN Creation Fulfillment routine to take actions to establish the remoteclient access, with one example of such a routine being described ingreater detail with respect to FIG. 8.

After block 425, or if it is instead determined in block 422 that theaccess information does not indicate to initiate the creation of an VPNconnection at a remote client location, the routine continues to block430 to use other specified access constraint information for theindicated computer network to configure allowable access for theindicated computer network. As described in greater elsewhere, suchconfiguration information may include constraints as to whether any ofthe computing nodes of the computer network are allowed to have accessto the Internet or otherwise outside the computer network, as well as tooptionally specify communication access policies between computing nodesof the computer network (including remote parts of the computer networkif the indicated computer network is an extension to a remote computernetwork). Accordingly, in block 430, the routine takes one or moreactions that may include, for example, configuring routing informationto be used by node communication manager modules and/or externalcommunication manager modules that support the computer network (e.g.,by sending a message to those communication manager modules with theinformation to be configured), as described in greater detail elsewhere.Furthermore, if actions were taken in block 425 to establish a VPNconnection from a remote client location to the provided computernetwork, the actions taken in block 430 may further include takingactions to support such a VPN connection by the provided computernetwork or otherwise by the configurable network service on behalf ofthe provided computer network, such as by configuring the providedcomputer network to accept such a VPN connection and to use appropriateinformation to decrypt communications that are encrypted for the VPNconnection.

After block 430, or if it instead determined in block 420 that theindication in block 405 does not include access information, the routinecontinues to block 440 to determine whether the indication in block 405includes network address information for an indicated computer network,such as one or more network address ranges and/or network addressesspecified in another form. If so, the routine continues to block 445 tostore the specified network address information for use with thecomputing nodes of the indicated computer network, and may furtherproceed to associate those specified network addresses with thecomputing nodes of the indicated computer network if those computingnodes have already been selected or otherwise put into use, such as withrespect to blocks 415 and/or 462. The associating of specified networkaddresses with computing nodes of a computer network may further includeconfiguring routing information to be used by node communication managermodules and/or external communication manager modules that support thecomputer network, as described in greater detail elsewhere. After block445, or if it is instead determined in block 440 that the indicationreceived in block 405 did not include network address information, theroutine continues to block 455 to determine whether the indicationreceived in block 405 includes network topology information for anindicated computer network. If so, the routine continues to block 457 tostore the network topology information for the indicated computernetwork, and to optionally proceed to configure that indicated computernetwork in accordance with the network topology information. Theconfiguring of network topology information may include configuringrouting information to be used by node communication manager modulesand/or external communication manager modules that support the computernetwork, such as to simulate actions of virtual networking devices thatare part of the specified topology information, as described in greaterdetail elsewhere.

After block 457, or if it instead determined in block 455 that theindication in block 405 does not include network topology information,the routine continues to block 460 to determine whether the indicationin block 405 includes an indication to add computing nodes to anindicated computer network, such as if the indicated computer networkhas been configured to include a specified quantity of computing nodesbut less than that specified quantity have been selected and put intouse. Furthermore, in some embodiments, a client may modify an existingcomputer network being provided by the configurable network service invarious manners even after use of the computer network has been ongoing,including to modify the quantity of computing nodes of the computernetwork and/or to modify that network topology information for thecomputer network, as discussed in greater detail elsewhere. If it isdetermined in block 460 that the indication is to add one or morecomputing nodes, the routine continues to block 462 to select one ormore computing nodes to be added to the indicated computer network froma group of available computing nodes of the configurable networkservice. As described in greater detail elsewhere, such computing nodesmay be selected in various manners. In block 464, the selected computingnodes are then added to the computer network, such as in a mannersimilar to that previously discussed (e.g., by associating appropriatenetwork address information with those selected computing nodes, bysetting access rights for those selected computing nodes in accordancewith any specified network topology information and/or other accessconstraint information for the computer network extension, etc.).

After block 464, or if it is instead determined in block 460 that theindication in block 405 is not to add computing nodes, the routinecontinues to block 470 to determine whether the indication in block 405is to add configured access for an indicated computer network to anindicated remote resource service. If so, the routine continues to block475 to configure an access mechanism for the indicated computer networkto access the indicated remote resource service, such as by mapping oneor more network addresses for the indicated computer network to thatremote resource service, by configuring routing information to be usedby node communication manager modules and/or external communicationmanager modules that support the computer network, by configuringactions to be taken by external communication manager modules forcommunications that use the access mechanism, etc. The routine thencontinues to block 478 to determine whether the remote resource servicehas a particular namespace for the resources that are to be accessiblefrom the indicated computer network and/or has one or more additionalaccess control indicators for the indicated computer network for usewith the resources, such as may be indicated in block 405 or otherwiseautomatically determined by the configurable network service, and if sothe routine continues to block 480 to associate that namespaceinformation and/or the access control indicator information with theconfigured access mechanism for the remote resource service.

After block 480, or if it is instead determined in block 478 that anamespace and/or additional access control indicators are not to be usedor in block 470 that the indication in block 405 is not to provideaccess to an indicated remote resource service, the routine continues toblock 490 to optionally perform one or more other indicated operationsas appropriate. For example, after completing the configuration of aparticular computer network for a client, the routine may further takeone or more final steps to provide access to the computer network fromremote sources, such as from a remote computer network to which acreated new computer network extension belongs. Such providing of accessmay include, for example, providing information to the client to enablethe client to access the computer network (e.g., a publicly accessiblenetwork address for a VPN to the computer network), configuring thecomputer network to accept communications from the remote client, etc.In addition, the routine may further perform other operations at times(e.g., periodically, when current conditions exceed a specifiedthreshold or otherwise trigger a specified condition, etc.), such as toping or otherwise check the status of some or all computing nodes forsome or all computer networks, monitor the use of some or all computernetworks by remote clients, monitor the use of internal configurablenetwork service resources by some or all provided computer networks,establish and maintain accounts of clients with the configurable networkservice, respond to requests from clients for status information abouttheir accounts or about their provided computer networks, obtain paymentfrom clients for use of the configurable network service, reduce aquantity of computing nodes for an indicated computer network, modifythe particular computing nodes that are part of an indicated computernetwork (e.g., by moving one or more executing programs from a computingnode at a first geographical location to a new computing node at asecond geographical location), etc. After block 490, the routinecontinues to block 495 to determine whether to continue, such as untilan explicit indication to terminate is received. If it is determined tocontinue, the routine returns to block 405, and if not continues toblock 499 and ends.

FIG. 5 is a flow diagram of an example embodiment of a NodeCommunication Manager routine 500. The routine may be provided by, forexample, execution of the CNS node communication manager modules 209 a,209 d, and 250 of FIG. 2, such as to control communications to and fromassociated computing nodes of provided computer networks in at leastsome embodiments. The routine 500 may, in at least some embodiments, beexecuted by each of a number of node communication manager modules ofthe configurable network service that are each associated with one ormore of the computing nodes provided by the configurable networkservice, and each of the node communication manager modules may beprovided in various manners (e.g., as part of a virtual machine monitorhypervisor for a physical host computing system on which other virtualmachine computing nodes execute, as a standalone proxy computing systemor other computing system that controls communications to and from oneor more computing nodes of provided computer networks, etc.). Inparticular, in the illustrated embodiment, the node communicationmanager modules facilitate the providing of computer networks forclients by using virtual networks that are overlaid on one or moreunderlying physical substrate networks used by the configurable networkservice to interconnect the various computing nodes of the configurablenetwork service, although in other embodiments the provided computernetworks may have forms other than virtual networks and/or overlaynetworks. Furthermore, as described in greater detail elsewhere, thenode communication manager modules in the illustrated embodiment providefunctionality in accordance with specified network topology informationfor provided computer networks, such as by implementing thefunctionality of simulated virtual or phantom networking devices orotherwise handling communications in a manner consistent with suchnetworking devices being present, although in other embodiments thenetwork topology information for a provided computer network may insteadbe provided in other manners (e.g., by using actual physical networkingdevices that correspond to the network topology).

The illustrated embodiment of the routine begins at block 505, where anindication is received of a node communication or other message. Theroutine continues to block 510 to determine the type of indicatedmessage and to proceed accordingly. In particular, if the indicatedmessage is determined to be an incoming node communication intended forone or more destination computing nodes associated with thecommunication manager module to which the routine corresponds, theroutine continues to block 515 to determine the one or more intendeddestination computing node(s) for the incoming node communication. Forexample, the incoming communication may be directed to a nodecommunication manager module over one or more underlying substratenetworks, and the header or other portion of the communication sent viathe substrate network may include information about a virtual networkaddress of a destination computing node that is part of a virtualprovided computer network, or may otherwise indicate the destinationcomputing node. As discussed below with respect to block 525, thehandling of the incoming communication via the substrate network mayfurther include modifying the communication in a manner appropriate forthe provided computer network to which the destination computing nodebelongs, such as by re-headering the communication to use virtualnetwork addresses for the destination and source computing nodes.

After block 515, the routine continues to block 520 to verify that theincoming communication is allowable for the intended destinationcomputing node(s). As discussed in greater detail elsewhere, theincoming communications may be determined to be allowable or unallowablein various manners, such as to provide firewall capabilities or otheraccess control so that only communications from specified othercomputing nodes are allowed (e.g., other computing nodes that are partof the same provided computer network) and/or so that only specifiedtypes of communications are allowed (e.g., for at least somecommunications from other computing systems, only if the communicationsare responses to other communications that were sent to those computingsystems from one of the computing nodes of a provided computer network).As previously noted, the determination of whether the communication isallowable may be made based at least in part on configurationinformation that was previously specified for the node communicationmanager module to which the routine corresponds, such as in a mannerspecific to the destination computing node(s) and/or the providedcomputer network to which those destination computing node(s) belong(e.g., based on the specified network topology information for theprovided computer network to which the destination computing node(s)belong and/or other access constraint information specified for thatprovided computer network). In addition, in embodiments in which anoverlay virtual network is used for the provided computer network towhich the destination computing node(s) belong, the verifying of theincoming communication may be based in part on information about theoverlay network and/or about the substrate network that is included inthe incoming communication by the configurable network service after thecommunication is sent by the initial sending computing node, such as toverify that the communication was actually sent by the purported sender.

If it is determined that the incoming communication is allowable, theincoming communication is provided in block 525 to the one or moredestination node(s) for the communication, such as by forwarding thecommunication over one or more connections or communication linksbetween the node communication manager module and the destinationcomputing node(s). In embodiments in which the incoming communicationwas sent via an underlying substrate network, the incoming communicationmay first be modified so that it is consistent with the providedcomputer network, such as by re-headering the incoming communication ina manner consistent with the provided computer network (e.g., to usevirtual network addresses corresponding to the provided computer networkfor the destination and source computing nodes). In addition, while notillustrated here, if the communication is not determined to be allowablein block 520, the routine may take various other actions, such as todrop the outgoing node communication without any indication to thesending computing node, return an error message to the sending computingnode, attempt to modify the outgoing communication to be allowable, etc.

If it is instead determined in block 510 that the indicated message inblock 505 is an outgoing node communication from an associated computingnode of a provided computer network that is managed by the nodecommunication manager module to which the routine corresponds, theroutine continues instead to block 530 to first verify whether theoutgoing communication is allowable, such as in a manner similar to thatpreviously described with respect to block 520. As discussed in greaterdetail elsewhere, the determination of whether the outgoingcommunication is allowable may be made in various manners in variousembodiments, including based on the specified network topologyinformation for the provided computer network to which the sendingcomputing node belongs and/or other access constraint informationspecified for that provided computer network. In the illustratedembodiment, the provided computer networks are virtual overlay networks,and the communications between computing nodes are actually sent via oneor more underlying substrate networks. Accordingly, after block 530, theroutine continues to block 535 to determine one or more substratedestination network addresses that correspond to the one or moredestination computing nodes or other destination computing systems forthe outgoing communication (e.g., to one or more remote nodecommunication manager modules that manage communications for thosedestination computing nodes, to an external communication manager modulethat manages communications for external destination computing systems,etc.), as described in greater detail elsewhere. The routine thencontinues to block 540 to forward the outgoing node communication to theintended destination(s) by using the determined substrate destinationnetwork address(es). In a manner similar to that described with respectto block 525, the forwarding of the node communication via theunderlying substrate network may include modifying the outgoingcommunication so that it is consistent with the substrate network, suchas by re-headering the outgoing communication in a manner consistentwith the substrate network (e.g., to use the determined substratedestination network addresses and/or to include information about thevirtual network addresses for the destination and source computingnodes), as described in greater detail elsewhere.

If it is instead determined in block 510 that another type of indicatedmessage was received in block 505, the routine continues instead toblock 590 to perform one or more other indicated operations asappropriate. For example, other types of messages may includeconfiguration information or other administrative messages from theconfigurable network service manager routine 400 of FIG. 4 (e.g., tospecify routing information or other configuration information to beused by the routine 500 for one or more provided computer networks towhich this instance of the routine 500 corresponds), from other nodecommunication manager routines (e.g., to propagate configurationinformation for provided computer networks), etc. Similarly, in somesituations the routine may in block 590 take actions to sendconfiguration information for provided computer networks to other nodecommunication manager modules, such as to distribute such information ina peer-to-peer manner after receiving the information from another nodecommunication manager module or from the configurable network servicemanager module. Other actions may include various types ofadministrative or housekeeping actions in at least some embodiments andsituations, such as to check the status of some or all computing nodesfor some or all computer networks, monitor the use of some or allcomputer networks by remote clients, monitor the use of internalconfigurable network service resources by some or all provided computernetworks, etc. After blocks 525, 540, or 590, the routine continues toblock 595 to determine whether to continue, such as until an explicitindication to terminate is received. If it is determined to continue,the routine returns to block 505, and if not continues to block 599 andends.

Thus, the routine 500 manages a variety of types of communications toand from computing nodes that are part of computer networks provided bythe configurable network service. While not separately illustrated inthis example embodiment of the routine, it will be appreciated that theroutine 500 may further perform configurations for at least somecommunications to allow one or more responses to previously sentcommunications, such as to initiate a session or other series ofcommunications. Thus, for example, a particular computing node of aprovided computer network may be configured to not accept communicationsfrom at least some other computing systems (e.g., external computingsystems), but may allow communications from those other computingsystems if they are responses to communications initially sent from thatparticular computing node. Accordingly, the determination in block 520may further be based in part on whether the incoming communication is aresponse to a previous outgoing communication that was handled withrespect to blocks 530-540.

FIG. 6 illustrates a flow diagram of an example embodiment of anExternal Communication Manager routine 600. The routine may be providedby, for example, execution of the external communication manager module270 of FIG. 2, such as to manage communications that pass into or out ofa data center or other group of computing nodes controlled by theconfigurable network service (e.g., between that group of controlledcomputing nodes and other computing systems that are at locationsexternal to those controlled computing nodes, such as remote locationsof clients, remote resource services, and other places generallyaccessible on the Internet or other public networks). As described ingreater detail elsewhere, the one or more external communication managermodules in the illustrated embodiment provide functionality inaccordance with specified access constraint information for providedcomputer networks and in accordance with specified configurationinformation for accessing particular remote resource services, such asby handling communications in a manner consistent with firewalls andother accessibility information specified by clients for their providedcomputer networks and/or specified by the configurable network servicefor its provided computer networks. In addition, in the illustratedembodiment, the computer networks that are provided by the configurablenetwork service are virtual overlay networks that use one or moreunderlying physical substrate networks that interconnect the computingnodes provided by the configurable network service, although in otherembodiments the provided computer networks may be implemented in othermanners (e.g., without using virtual networks and/or overlay networks).

The illustrated embodiment of the routine begins in block 605, where anindication is received of a communication to or from a computing node ofa provided computer network or of another message. After block 605, theroutine in block 610 determines the type of indicated message that isreceived, and proceeds accordingly. In particular, if the indicatedmessage is incoming to the computing nodes controlled by theconfigurable network service and is intended for one or more destinationcomputing nodes on a provided computer network (e.g., via a VPNconnection from a remote location of the client on whose behalf thecomputer network is provided, from an external computing system via theInternet, etc.), the routine continues to block 612. In block 615, theroutine first determines whether the incoming communication was sent viaa client's VPN connection, and if so continues to block 620 tooptionally decrypt or otherwise decode the communication (e.g., if othersoftware of the configurable network service has not already handledsuch management of communications received via the VPN connection). Inother embodiments, blocks 615 and 620 may not be performed, such as ifother software and/or hardware of the configurable network servicemanages such communications received via a VPN connection before theyare received in block 605. After block 620, or if it is insteaddetermined in block 615 that the incoming communication is not receivedvia a VPN connection, the routine continues to block 625.

Blocks 625-629 are performed in a manner similar to those of blocks530-540 of FIG. 5. In particular, in block 625, the routine firstverifies whether the incoming communication is allowable, such as basedat least in part on specified network typology information for theprovided computer network to which the destination computing node(s)belong and/or based on other access constraint information for thatprovided computer network. If the communication is verified to beallowable, the routine continues to block 627 to determine one or moredestination substrate network addresses that correspond to thedestination computing node(s). In block 629, the routine then forwardsthe communication to the determined destination network addresses on thesubstrate network, such as to eventually be handled by one or more nodecommunication manager modules as previously described with respect toblocks 515-525 of FIG. 5. As previously noted, if the communication isnot verified to be allowed in block 625, various other actions mayinstead be taken, such as to drop the communication. In addition, theforwarding of the communication on the substrate network may includemodifying the communication in one or more manners to be consistent withthe substrate network, as discussed in greater detail elsewhere.Furthermore, while not illustrated here, in at least some embodiments,the routine may perform other functionality consistent withcommunications incoming to a group of controlled computing nodes (e.g.,from a public network to a private network), such as functionality toprovide network address translation (“NAT”) and/or port addresstranslation (“PAT”), to provide general firewall or proxy or othersecurity functionality for the configurable network service, etc.

If it is instead determined in block 610 that the indicated message isnot an incoming communication to a computing node of a provided computernetwork, but is instead a communication that is received over theinternal substrate network from a computing node of a provided computernetwork and is outgoing to one or more external destination computingsystems (e.g., via a VPN connection to a remote computer network of aclient or other remote computing system of a client, over the Internetto a publicly accessible system, etc.), the routine continues to block630. Blocks 630, 635, and 645 are performed in a manner similar toblocks 515-525 of FIG. 5. In particular, in block 630, the routinedetermines one or more intended destination computing systems at one ormore remote locations for the outgoing communication, such as based oninformation in the communication received via the substrate network. Inblock 635, the routine then verifies whether the communication isallowable, such as in a manner similar to that previously described(e.g., by considering specified network topology information and/oraccess constraint information for the provided computer network to whichthe sending computing node belongs). After block 635, the routinecontinues to block 640 to determine whether the outgoing communicationis being sent via a VPN connection to one or more remote clientcomputing systems, such as part of a remote computer network of theclient. If so, the routine continues to block 642 to optionally encryptor otherwise encode the communication for the VPN connection (e.g., ifother software and/or hardware of the configurable network service doesnot handle such management of communications sent via the VPNconnection), and then forwards the communication to the determineddestination computing systems via the VPN connection. In otherembodiments, separate software and/or hardware that maintains the VPNconnection will instead perform such operations. If it is insteaddetermined in block 640 that the outgoing communication is not beingsent via a VPN connection, the routine continues instead to block 645 toforward the communication to the determined destination computingsystems over the Internet or other public networks. As previouslydescribed, the routine may further modify such outgoing communicationsthat are received via the substrate network before they are forwardedexternally, such as to re-header the outgoing communication in a mannerconsistent with the computer networks over which the communication willtravel. Furthermore, while not illustrated here, in at least someembodiments, the routine may perform other functionality consistent withcommunications outgoing from a group of controlled computing nodes(e.g., from a private network to a public network), such asfunctionality to provide network address translation (“NAT”) and/or portaddress translation (“PAT”), to provide general firewall or proxy orother security functionality for the configurable network service, etc.

If it instead determined in block 610 that the indicated message is froma computing node on a provided computer network to access a remoteresource service that has a configured access mechanism for thatprovided computer network, the routine continues instead to block 650 toexecute the Remote Resource Service Access routine, with one exampleembodiment of that routine described in greater detail with respect toFIG. 7. Otherwise, the routine continues to 690 to perform one or moreother indicated operations as appropriate, such as in response to otherreceived messages or received information. Such other indicatedoperations may have various forms, such as discussed in greater detailwith respect to block 590 of FIG. 5. For example, other types ofmessages may include configuration information or other administrativemessages from the configurable network service manager routine 400 ofFIG. 4 (e.g., to specify routing information or other configurationinformation to be used by the routine 600 for one or more providedcomputer networks), from node communication manager routines (e.g., topropagate configuration information for provided computer networks),etc. Similarly, in some situations the routine may in block 690 takeactions to send configuration information for provided computer networksto node communication manager modules, such as to distribute suchinformation in a peer-to-peer manner after receiving the informationfrom other node communication manager modules or from the configurablenetwork service manager module. Other actions may similarly includevarious types of administrative or housekeeping actions in at least someembodiments and situations, such as to check the status of some or allcomputing nodes for some or all computer networks, monitor the use ofsome or all computer networks by remote clients, monitor the use ofinternal configurable network service resources by some or all providedcomputer networks, etc.

After blocks 629, 642, 645, 650, or 690, the routine continues to block695 to determine whether to continue, such as until an explicitindication to terminate is received. If it is determined to continue,the routine returns to block 605, and otherwise continues to block 699and ends.

Thus, the routine 600 manages a variety of types of communications toand from computing nodes that are part of computer networks provided bythe configurable network service. While not separately illustrated inthis example embodiment of the routine, it will be appreciated that theroutine 600 may further perform configurations for at least somecommunications to allow one or more responses to previously sentcommunications, such as to initiate a session or other series ofcommunications. Thus, for example, a particular provided computernetwork may be configured to prevent any external computing systems frominitiating communications to computing nodes of that computer network,but may allow such an external computing system to respond to acommunication that is initially sent from a computing node of thatcomputer network to that external computing system. Accordingly, thedetermination in block 625 may further be based in part on whether theincoming communication is a response to a previous outgoingcommunication that was handled with respect to blocks 630-645.Similarly, for communications that are initiated to access remoteresource services, as discussed in greater detail with respect to block650, responses from the remote resource services may be configured to beallowed, such as with respect to blocks 615-629, or instead in anothermanner.

FIG. 7 is a flow diagram of an example embodiment of a Remote ResourceService Access routine 700. The routine may be provided by, for example,execution of the external communication manager module 270 of FIG. 2,such as may be initiated by execution of block 650 of FIG. 6. Theroutine manages communications made by computing nodes of providedcomputer networks to remote resource services, and in particular toremote resource services to which the provided computer networks havepreviously been configured to provide specialized access, such as inconjunction with blocks 475-480 of FIG. 4. As discussed in greaterdetail elsewhere, in at least some embodiments, a provided computernetwork may be configured to provide specialized access to a particularremote resource service (e.g., by assigning one or more networkaddresses on that provided computer network to represent the remoteresource service), and a substrate physical network may be configured toforward corresponding communications to an external communicationmanager module that manages external communications, with the externalcommunication manager module being configured to manage those forwardedcommunications as appropriate.

In the illustrated embodiment, the routine begins at block 705, where anindication is received of a communication from a computing node on aprovided computer network to a remote resource service for which aconfigured access mechanism is provided for that computer network, suchas based on the network address used for the communication. The routinethen continues to block 710, where it retrieves configurationinformation that was previously specified for the access mechanism usedfor the communication. In block 715, the routine then determines thedestination remote resource service for which the communication isintended, such as based on the retrieved configuration information.

After block 715, the routine continues to block 725 to determine whetherthe communication is allowable, such as in a manner similar to thatdiscussed with respect to blocks 520 and 530 of FIG. 5 and blocks 625and 635 of FIG. 6. Furthermore, the determination may further be made inat least some situations and embodiments based on the retrievedconfiguration information for the access mechanism used, such as to onlyallow certain types of communications for certain configured accessmechanisms. If the communication is determined to be allowable, theroutine then continues to block 730 to optionally modify thecommunication in a manner based on the previous configuration for theaccess mechanism used. For example, as discussed in greater detailelsewhere, an access mechanism may be configured to modifycommunications to correspond to a particular namespace used by a remoteresource service, to include information about the provided computernetwork of the computing node that send the communication or otherinformation about the location of the computing node for authenticationpurposes by the remote resource service, etc.

The routine then continues to block 735 to optionally perform additionalauthentication-related activities for the communication in a mannerspecific to the determined remote resource service. For example, asdiscussed in greater detail elsewhere, at least some remote resourceservices may be affiliated with the configurable network service orotherwise allow the configurable network service to access the remoteresource service in a privileged manner that is not provided tounauthenticated requesters communicating with the remote resourceservice over public networks. If so, the routine may performauthentication-related activities that, for example, enable the remoteresource service to determine that the communication is being sent froma trusted or otherwise known requester, such as by modifying thecommunication to include an identifier that corresponds to theconfigurable network service (e.g., based on prior interactions betweenthe configurable network service and the remote resource service, suchas by including a digital signature based on the identifier as part ofthe modified communication).

After block 735, the routine then continues to block 745 to optionallyencrypt the communication or otherwise access a secure connection to thedetermined remote resource service (e.g., a VPN connection with aparticular affiliated remote resource service, a dedicated private leaseline or other communication link to the remote resource service, etc.),and forwards the communication to the determined remote resourceservice. The communication being forwarded may, for example, be sentover the Internet or one or more other public networks, or may insteadin some embodiments be sent via a private communication link or othersecure connection. After block 745, the routine continues to block 799and ends.

FIG. 8 is a flow diagram of an example embodiment of a VPN CreationFulfillment routine 800. The routine may be provided by, for example,execution of the configurable network service manager module, such asmay be initiated based on execution of block 425 of FIG. 4 resultingfrom a client invocation of a remote access establishment API providedby an embodiment of the configurable network service.

In the illustrated embodiment, the routine begins at block 805, where anindication is received of a client request to establish a VPN connectionfrom a remote location of the client (e.g., a remote private computernetwork of the client) to a provided computer network for the client(e.g., a network extension that is provided by the configurable networkservice for the remote private computer network of the client). In atleast some embodiments, the request by the client to establish the VPNconnection is part of a request to fulfill an order for one or moreappropriate networking devices and corresponding software and/orconfiguration information to be provided to the remote location of theclient, so as to enable the VPN connection to be established from one ormore computing systems at the remote client location to the computernetwork provided for the client by the configurable network service. Inat least some such embodiments, the fulfillment of the order may beperformed by the configurable network service without any furtheractions by the client after the invocation of the remote accessestablishment API or other initiation of the request from the client,while in other embodiments some additional interactions with the clientmay be performed as part of the fulfillment of the order (e.g.,presenting options to the client, obtaining additional information fromthe client, obtaining payment information from the client, etc.).

In block 815, the routine then obtains various information about theclient for use in fulfilling the request, such as may be supplied in therequest received in block 805, previously received from the client andretrieved from an account of the client with the configurable networkservice, and/or dynamically obtained from the client and/or one or moreexternal sources. The obtained information may have various forms, suchas information about a geographical location of the client to whichnetworking device(s) and other items may be physically delivered, anelectronic communication address to which electronic information may beelectronically delivered, payment information via which the client willpay a fee associated with the request received in block 805, etc. Inaddition, various information may be obtained to assist in configuringthe VPN connection between the remote client location and the providedcomputer network for the client, such as a network address that ispublicly accessible from the remote client location (or othercorresponding connection information) to initiate the VPN connection, aunique identifier or other information for use in identifying theprovided computer network to which the VPN connection is to beestablished, etc.

After block 815, the routine continues to block 825 to determine one ormore appropriate networking devices for use with the client's one ormore remote computing systems to establish the VPN connection to theprovided computer network. As discussed in greater detail elsewhere, theappropriate networking devices may be determined in various manners,such as based on information specific to the provided computer networkfor the client, to the remote computing systems of the client, and/or tothe configurable network service (e.g., based on networking devices usedas part of the substrate network of the configurable network service orother infrastructure of the configurable network service). Furthermore,the determination of the appropriate networking device(s) may be made invarious manners in various embodiments, such as automatically by theconfigurable network service and/or based at least in part oninformation from the client (e.g., based on a selection by the client aspart of the request received in block 805 or as otherwise specified bythe client, such as to choose between multiple alternatives presented tothe client).

After block 825, the routine continues to block 835 to generateconfiguration information for the determined networking device(s) foruse in preparing the networking device(s) to connect to the providedcomputer network for the client, although in other embodiments theroutine may instruct a third-party entity to generate the configurationinformation (e.g., the same retailer that will be contacted in block845). In at least some embodiments, the configuration information forthe determined networking devices will cause the configured networkingdevices to initiate contact with the configurable network service tocomplete the configuration of the configured networking devices (e.g.,by obtaining additional information from the configurable networkservice to configure the networking device(s) in a manner specific to aparticular provided computer network). In addition, in at least someembodiments, the configuration information for the determined networkingdevices will cause the configured networking devices to initiate contactwith the client's provided computer network, such as to establish theVPN connection to the provided computer network. The generatedconfiguration information may in some embodiments be specific to thetypes of determined networking device(s) and/or to the provided computernetwork to which the determined networking device(s) will establish theVPN connection, and the generating of the configuration information mayinclude retrieving previously prepared configuration information and/ordynamically creating new configuration information (e.g., by modifyingpreviously prepared configuration information in a manner specific tothe determined networking device(s) and/or to the provided computernetwork, such as if the previously prepared configuration information isfor use with any networking device(s) and/or with any provided computernetworks). The generated configuration information may similarly havevarious forms, such as configured software to be executed on a hardwaredevice, textual instructions for use by a human operator at the remotelocation, etc.

In block 845, the routine then initiates an order with a retailer tosupply the determined networking device(s) to the remote client locationfor use with one or more remote computing systems of the client, and inthe illustrated embodiment to further initiate supplying the generatedconfiguration information to the client for use with the networkingdevices. In such embodiments, the generated configuration informationmay be provided to the retailer in various manners, such as by sendingthe configuration information as part of the order, by previouslyinstructing the retailer in block 835 to generate the configurationinformation, etc. As discussed in greater detail elsewhere, thegenerated configuration information may be supplied to the client invarious manners, including one or more of the following: by storing thegenerated configuration information on a physical device-readablestorage medium (e.g., a CD, DVD, USB memory key, etc.) that isphysically delivered to the client; by configuring the networkingdevice(s) with the generated configuration information before they aredelivered to the client (e.g., by loading the generated configurationinformation onto the networking device(s) at a fulfillment center usedby the retailer); by transmitting the generated configurationinformation to the client electronically; etc. In other embodiments, thenetworking device(s) and/or the configuration information may beprovided to the client in other manners, such as by having one or bothof the networking devices and generated configuration supplied directlyby the configurable network service rather than a retailer, by using afirst retailer to supply the networking devices and a distinct secondretailer to supply the generated configuration information, by using oneor more third parties that are not retailers, etc. After block 845, theroutine continues to block 899 and returns.

It will also be appreciated that in some embodiments the functionalityprovided by the routines discussed above may be provided in alternativeways, such as being split among more routines or consolidated into fewerroutines. Similarly, in some embodiments illustrated routines mayprovide more or less functionality than is described, such as when otherillustrated routines instead lack or include such functionalityrespectively, or when the amount of functionality that is provided isaltered. In addition, while various operations may be illustrated asbeing performed in a particular manner (e.g., in serial or in parallel)and/or in a particular order, those skilled in the art will appreciatethat in other embodiments the operations may be performed in otherorders and in other manners. Those skilled in the art will alsoappreciate that the data structures discussed above may be structured indifferent manners, such as by having a single data structure split intomultiple data structures or by having multiple data structuresconsolidated into a single data structure. Similarly, in someembodiments illustrated data structures may store more or lessinformation than is described, such as when other illustrated datastructures instead lack or include such information respectively, orwhen the amount or types of information that is stored is altered.

From the foregoing it will be appreciated that, although specificembodiments have been described herein for purposes of illustration,various modifications may be made without deviating from the spirit andscope of the invention. Accordingly, the invention is not limited exceptas by the appended claims and the elements recited therein. In addition,while certain aspects of the invention are presented below in certainclaim forms, the inventors contemplate the various aspects of theinvention in any available claim form. For example, while only someaspects of the invention may currently be recited as being embodied in acomputer-readable medium, other aspects may likewise be so embodied.

1. A method for a computing system of a configurable network service toprovide access to private computer networks, the method comprising:providing a programmatic interface for the configurable network serviceto enable remote users to create and configure network extensions toremote private computer networks of the remote users, the configurablenetwork service including a plurality of computing systems that are foruse in providing the created network extensions to the remote users; andunder control of the computing system of the configurable networkservice, and for each of multiple remote users, receiving configurationinformation that is programmatically provided by the remote user via theprovided programmatic interface to create and configure a local privatenetwork extension to a remote private computer network of the user, theprivate network extension being provided by the configurable networkservice and including a subset of multiple of the plurality of computingsystems, the received configuration information including user-specifiednetwork topology information for the private network extension and auser-specified subset of multiple network addresses of the privatecomputer network that are to be assigned to the multiple computingsystems, the received configuration information further including anindication of a remote resource service that is external to the privatecomputer network of the user and that is to be accessible from themultiple computing systems of the private network extension;automatically configuring the private network extension of the user toprovide private access between the private computer network of the userand the multiple computing systems of the private network extension ofthe user, the configuring including establishing a virtual privatenetwork connection between the private network extension and the privatecomputer network of the user and configuring communications within theprivate network extension to be routed in accordance with the specifiednetwork topology information; automatically generating a uniqueidentifier for the private network extension to represent a newnamespace within the indicated remote resource service, the remoteresource service providing computing-related resources to multipleusers, the represented namespace to include one or morecomputing-related resources provided by the remote resource service thatare accessible only from the private network extension; automaticallyconfiguring the private network extension of the user to enable accessfrom the multiple computing systems of the private network extension tothe one or more computing-related resources provided by the remoteresource service within the represented namespace, the configuringincluding assigning one of the user-specified subset of networkaddresses to represent the remote resource service and associating theunique identifier with the assigned network address, so thatcommunications sent to the remote resource service via the assignednetwork address are modified to include the unique identifier for use bythe remote resource service in identifying the represented namespace;and providing the private access between the multiple computing systemsof the private network extension and the private computer network of theuser.
 2. The method of claim 1 wherein, for one of the multiple users,the network topology information in the received configurationinformation further specifies one or more networking devices to separatethe multiple computing systems of the private network extension for theone user into different groups having different inter-communicationcharacteristics, the received configuration information further includesan indication that the multiple computing systems of the private networkextension for the one user are not allowed to access computing systemshaving network addresses that are not part of the multiple networkaddresses of the private computer network of the user, and the automaticconfiguring of the private network extension of the one user to providethe private access from the private computer network of the one user tothe private network extension of the one user includes creating virtualdevices to simulate the specified one or more networking devices andincludes configuring one or more actual networking devices to preventcommunications between the private computer network of the one user andany computing systems external to the private computer network of theone user.
 3. The method of claim 2 wherein the configurable networkservice is a fee-based service that is accessible to the remote usersvia public networks and that provides the network extensions using cloudcomputing techniques, and wherein the multiple remote users arecustomers of the configurable network service who provide payment to theconfigurable network service for the created network extensions providedto the users by the configurable network service.
 4. Acomputer-implemented method for providing access to private computernetworks, the method comprising: under control of a computing system fora configurable network service that provides a programmatic interfacefor use by multiple clients to configure private computer networks foruse by the multiple clients, receiving first information that isprogrammatically provided by a first client via the programmaticinterface to configure a first private computer network for use by thefirst client, the first private computer network including a group ofmultiple of a plurality of computing nodes provided by the configurablenetwork service, the multiple computing nodes each being configured tobe associated with at least one of multiple network addresses specifiedin the first information for use with the first private computernetwork; obtaining second information to configure access from the firstprivate computer network to a subset of computing-related resources thatare associated with a namespace within a network-accessible remoteresource service, the second information including an identifierassociated with the namespace within the remote resource service;automatically configuring the first private computer network to enableaccess from the multiple computing nodes to the subset ofcomputing-related resources provided by the remote resource service, theconfiguring including associating the identifier with an indicated oneof the multiple network addresses that represents the remote resourceservice, so that communications sent to the remote resource service viathe indicated network address to access the subset of computing-relatedresources are modified to include an indication of the identifier foruse by the remote resource service in identifying the namespace; andinitiating availability of access to the first private computer networkfrom one or more remote computing systems of the first client.
 5. Themethod of claim 4 wherein the first private computer network isconfigured to be an extension of a remote private computer network ofthe first client that includes multiple computing systems, wherein thespecified multiple network addresses are a subset of a plurality ofprivate network addresses used with the remote private computer network,and wherein the automatic configuring of the first private computernetwork is further to enable private access between the multiplecomputing systems of the remote private computer network of the firstclient and the multiple computing nodes of the first private computernetwork.
 6. The method of claim 5 wherein the initiating of theavailability of the access to the first private computer network fromthe one or more remote computing systems of the first client includesestablishing a secure connection between the remote private computernetwork and the first private computer network so as to provide theenabled private access.
 7. The method of claim 5 wherein the firstprivate computer network is provided by the configurable network serviceas a virtual network overlaid on one or more physical substrate networksof the configurable network service that interconnect the plurality ofcomputing nodes provided by the configurable network service, andwherein the specified multiple network addresses are virtual networkaddresses.
 8. The method of claim 4 wherein the first informationfurther includes additional information specified by the first clientfor use in configuring the first private computer network to controlcommunications between the multiple computing nodes of the first privatecomputer network, and wherein the method further comprises automaticallyconfiguring the first private computer network to allow and to blockcommunications between the multiple computing nodes in accordance withthe specified additional information.
 9. The method of claim 8 whereinthe specified additional information includes network topologyinformation that indicates at least one of one or more networkingdevices that are part of the first private computer network and one ormore subgroups of the multiple computing nodes that share commonintercommunication characteristics, wherein the automatic configuring ofthe first private computer network includes, if the network topologyinformation indicates the one or more networking devices, configuringone or more modules of the configurable network service to simulatepresence of the one or more networking devices, and wherein theautomatic configuring of the first private computer network includes, ifthe network topology information indicates the one or more subgroups,configuring one or more modules of the configurable network service tosimulate presence of the one or more subgroups.
 10. The method of claim4 wherein the first information further includes additional informationspecified by the first client for use in configuring the first privatecomputer network, the additional information including one or more of aquantity of the multiple computing nodes for the first private computernetwork, of one or more geographical locations at which at least some ofthe multiple computing nodes are located, and of one or more networkaccess constraints to control communications between the multiplecomputing nodes of the first private computer network and othercomputing systems external to the first private computer network, andwherein the method further comprises automatically selecting themultiple computing nodes for the first private computer network based onthe specified first information, and automatically configuring the firstprivate computer network in accordance with the specified additionalinformation.
 11. The method of claim 4 wherein the second information isobtained based at least in part on the first client programmaticallyproviding the second information via the programmatic interface, whereinthe provided second information includes the associated identifier forthe namespace, wherein at least some of the subset of computing-relatedresources exist at the remote resource service within the namespacebefore the providing of the second information, and wherein the methodfurther comprises obtaining one or more communications sent from one ormore of the multiple computing nodes to the indicated network address toaccess one or more of the existing at least some computing-relatedresources from the remote resource service, and forwarding the obtainedone or more communications to the remote resource after modifying theobtained one or more communications to include the indication of theidentifier.
 12. The method of claim 4 wherein the obtaining of theidentifier included in the second information includes the configurablenetwork service automatically interacting with the remote resourceservice to create the namespace for use with the first private computernetwork, the creating of the namespace including determining theidentifier for the namespace, and wherein the method further comprisesobtaining one or more communications sent from one or more of themultiple computing nodes to the indicated network address to create oneor more new computing-related resources from the remote resourceservice, and forwarding the obtained one or more communications to theremote resource after modifying the obtained one or more communicationsto include the indication of the identifier.
 13. The method of claim 4wherein the remote resource service is accessible over one or morepublic networks, and wherein the configuring of the first privatecomputer network to enable access from the multiple computing nodes tothe subset of computing-related resources includes configuring one ormore modules of the configurable network service to forwardcommunications sent to the indicated network address to the remoteresource service over the one or more public networks.
 14. The method ofclaim 4 further comprising obtaining third information to configureaccess from the first private computer network to a distinct secondsubset of computing-related resources that are associated with adistinct second namespace within the remote resource service, the thirdinformation including a distinct second identifier associated with thesecond namespace within the remote resource service, and automaticallyconfiguring the first private computer network to enable access from themultiple computing nodes to the second subset of computing-relatedresources by associating the second identifier with a second one of themultiple network addresses, so that communications sent to the remoteresource service via the second network address to access the secondsubset of computing-related resources are modified to include anindication of the second identifier for use by the remote resourceservice in identifying the second namespace.
 15. The method of claim 4wherein the computing-related resources associated with the namespacewithin the remote resource service include resources for at least one ofdata storage services and of program execution services and ofasynchronous message passing services, and wherein the method furthercomprises, under control of the remote resource service: receivingcommunications sent from the multiple computing nodes of the firstprivate computer network via the indicated network address to access atleast some of the subset of computing-related resources, the receivedcommunications including the indication of the identifier; and providingaccess to the at least some computing-related resources from thenamespace associated with the indicated identifier.
 16. The method ofclaim 4 wherein the multiple computing nodes are each a virtual machinehosted on one of multiple physical computing systems of the configurablenetwork service, and wherein the configuring of the first privatecomputer network includes configuring one or more virtual machinecommunication manager modules that execute on one or more of thephysical computing systems to manage communications for the hostedvirtual machines.
 17. The method of claim 4 wherein the private computernetworks configured by the multiple clients include one or moreconfigured private computer networks other than the first privatecomputer network for one or more clients other than the first clientthat have one or more network addresses specified by the one or moreother clients that are the same as at least one of the multiple networkaddresses specified for use with the first private computer network, andwherein the configurable network service further manages those samenetwork addresses such that, for each of those same network addresses,each of the other private computer networks has a computing nodecorresponding to the network address that is distinct from a computingnode corresponding to the network address for the first private computernetwork.
 18. The method of claim 4 wherein the configuring of the firstprivate computer network by the first client includes permitting thefirst client to select any network address for the multiple networkaddresses specified in the first information for use with the firstprivate computer network.
 19. The method of claim 4 wherein the firstinformation that is programmatically provided by the first client viathe programmatic interface is received based on one or more interactionsof the first client with a graphical user interface displayed to thefirst client on a computing device of the first client.
 20. Acomputer-readable medium whose contents enable a computing system of aconfigurable network service to provide access to private computernetworks, by performing a method comprising: for each of multiple remotecustomers of a configurable network service, receiving one or morerequests that are programmatically made by the remote customer toinitiate creation for the customer of a network extension for a remoteprivate network of the customer and to specify configuration informationfor the created network extension of the customer, the configurationinformation including network topology information for the creatednetwork extension of the customer; automatically selecting multiplecomputing nodes for use as part of the created network extension of thecustomer, the multiple computing nodes being a subset of a plurality ofcomputing nodes provided by the configurable network service and beingselected based at least in part on the configuration informationspecified by the customer; automatically configuring the created networkextension of the customer to use the multiple computing nodes so as toprovide private access of the customer to the created network extensionof the customer, the private access enabling intercommunications betweenthe multiple computing nodes and one or more computing systems of theremote private network of the customer, the intercommunications beingrouted via the created network extension in accordance with the networktopology information specified by the customer; and initiating theproviding of the private access of the customer to the created networkextension of the customer. 21.-30. (canceled)